Container sterilization method and container sterilization device

Abstract

Provided are a container sterilization method and a container sterilization device with which it is possible to achieve effective sterilization in a short time while avoiding or reducing any residual risk of a bactericide. A container sterilization method for sterilizing a container surface of a container or a container preform includes a laser irradiation process for irradiating the container surface with a CO2 laser, and a UV light irradiation process for irradiating the container surface with UV light.

Description

Container sterilization method and container sterilization device

[0001] The present invention relates to a container sterilization method and a container sterilization device for sterilizing the container surface of a container or a container preform.

[0002] Conventionally, a sterilization treatment using a sterilizing agent such as hydrogen peroxide has been known as a method for sterilizing the surface of a container or a container preform (see, for example, Patent Document 1).

[0003] JP 2010-202284 A

[0004] However, when using a disinfectant for sterilization, there is a concern that the disinfectant may remain in the molded container, and measures must be taken to reduce the risk of residue.

[0005] Therefore, the present invention aims to solve these problems and provide a container sterilization method and device that has a simple configuration and achieves effective sterilization in a short time while avoiding or reducing the risk of residual disinfectant.

[0006] One aspect of the container sterilization method of the present invention is a container sterilization method for sterilizing a container surface of a container or a container preform, the method comprising: applying CO ２ The above-mentioned problem is solved by including a laser irradiation process of irradiating a laser and a UV light irradiation process of irradiating the container surface with UV light. Another aspect of the container sterilization method of the present invention is a container sterilization method for sterilizing the container surface of a container or a container preform, which solves the above-mentioned problem by including a laser irradiation process of irradiating the container surface with a laser of an infrared wavelength and a UV light irradiation process of irradiating the container surface with UV light. One aspect of the container sterilization device of the present invention is a container sterilization device for sterilizing the container surface of a container or a container preform, which sterilizes the container surface with CO ２The above-mentioned problem is solved by including a laser irradiation means for irradiating a laser and a UV light irradiation means for irradiating the container surface with UV light. Another aspect of the container sterilization device of the present invention is a container sterilization device for sterilizing the container surface of a container or a container preform, which solves the above-mentioned problem by including a laser irradiation means for irradiating the container surface with a laser of an infrared wavelength and a UV light irradiation means for irradiating the container surface with UV light.

[0007] In either the container sterilization method or the container sterilization device, the CO ２ The irradiation area of ​​the laser and the irradiation area of ​​the UV light in the UV light irradiation process may overlap. In either of the container sterilization method or the container sterilization device, the UV light irradiation process may be performed by irradiating a UV laser. In either of the container sterilization method or the container sterilization device, the laser irradiation process and the UV light irradiation process may be performed by irradiating a CO ２ The sterilization may be carried out by mixing a laser and a UV laser and irradiating them from the same irradiation unit. In either of the above container sterilization methods or container sterilization devices, the sterilization ability against mold by the laser irradiation treatment may be set higher than the sterilization ability against mold by the UV light irradiation treatment. In either of the above container sterilization methods or container sterilization devices, the sterilization ability against spore-forming bacteria by the laser irradiation treatment may be set lower than the sterilization ability against spore-forming bacteria by the UV light irradiation treatment. Either of the above container sterilization methods or container sterilization devices may further include a heat treatment carried out before or simultaneously with the laser irradiation treatment, and the heat treatment may heat the area of ​​the container surface to be sterilized by the laser irradiation treatment. Either of the above container sterilization methods or container sterilization devices may further include a heat treatment of heating a preform as the container preform to a molding temperature when it is molded into a PET bottle as the container, and the laser irradiation treatment and the UV light irradiation treatment are carried out on the preform after the heat treatment, and CO 2 is applied to the mouth of the preform. ２ Integrated laser light intensity (mJ / cm ２ ) is the CO ２ Integrated laser light intensity (mJ / cm２ ) and / or the integrated amount of UV light (mJ / cm ) applied to the mouth of the preform ２ ) is the cumulative amount of UV light (mJ / cm ) applied to the body of the preform. ２ ) may be greater than .

[0008] The present invention has a simple configuration that can achieve effective sterilization in a short time while avoiding or reducing the risk of residual sterilant.

[0009] FIG. 1 is an explanatory diagram showing an aseptic filling system equipped with a container sterilization device according to one embodiment of the present invention. ２ 1 is an explanatory diagram showing an example of a laser and UV light irradiation mode. ２ The sterilization effect of UV light irradiation is shown in Fig. 1. The absorbance of spore-forming bacteria, mold, and PET resin with respect to the wavelength of light is shown in Fig. 1.

[0010] An aseptic filling system 10 according to one embodiment of the present invention will be described below with reference to the drawings. Note that the terms "upstream" and "downstream" used in this specification refer to the upstream and downstream sides in the conveying direction of the preforms P or containers.

[0011] First, the aseptic filling system 10 is configured as a so-called in-line blow type filling system that aseptically fills sterilized contents (particularly liquid contents) into sterilized containers, and as shown in Figure 1, it is equipped with an aseptic molding device 20 that aseptically molds containers, and a filling device 60 that aseptically fills the contents into the containers.

[0012] Each component of the aseptic filling system 10 will be described below with reference to the drawings.

[0013] First, the aseptic molding apparatus 20 aseptically molds sterilized containers that have been subjected to a sterilization treatment, and as shown in FIG. 1, it is equipped with an inlet section 21 into which preforms P, which are preliminary molded bodies for containers such as PET bottles, are introduced, a blow molding turret 22, an oven mechanism 30 that heats the preforms P in an oven area A1 set downstream of the inlet section 21, a preform conveying mechanism 40 that conveys the preforms P, and a container sterilization device 50 that sterilizes the preforms P.

[0014] As shown in FIG. 1, the inlet portion 21 is a portion for introducing the preforms P into the aseptic molding apparatus 20 (aseptic filling system 10).

[0015] 1, the blow molding turret 22 is disposed downstream of the oven area A1 and performs aseptic blow molding on the preforms P. Specifically, the blow molding turret 22 is configured as a turret equipped with a blow machine (not shown) that performs biaxial stretch blow molding of containers such as PET bottles by blowing aseptic air into the preforms P that have been heated to the molding temperature for aseptic blow molding.

[0016] The molding area A3, where the blow molding turret 22 is installed, is covered by a chamber and maintained at a sterile atmosphere and positive pressure by blowing sterile air passed through a HEPA filter from above using an FFU (Fan Filter Unit). Furthermore, the blow molding turret 22, blowing machine, and other equipment installed in the molding area A3 are sterilized down to the end of the blow piping. Preforms P, which have been sterilized only at the preform stage, are transported to the molding area A3 and aseptically blow-molded. This allows aseptic blow molding, in which blow molding is performed in a sterile environment, to be performed in the molding area A3. Therefore, it is not necessary to locally create a sterile air or sterilizing gas atmosphere near the transport path for transporting preforms P and blow-molded containers within the molding area A3, and it is also not necessary to sterilize the containers after blow molding.

[0017] The oven mechanism 30 performs a temperature raising process to raise the temperature of the preform P (of the body P1) to the molding temperature during aseptic blow molding in the blow molding turret 22, and has an oven chamber 31 with an oven area A1 inside, and a plurality of temperature raising heaters 32 configured as infrared heaters that raise the temperature of the preform P. Note that the oven mechanism 30 may be provided with a simple cover that surrounds the periphery of the oven instead of the oven chamber 31, or the oven chamber 31 may not be provided.

[0018] The body portion P1 of the preform P is a portion that is placed inside the mold during aseptic blow molding and is expanded within the mold, while the mouth portion P2 of the preform P is a portion that is placed outside the mold during aseptic blow molding and is not expanded.

[0019] As shown in FIG. 1, the transfer area A2 is an area downstream of the oven area A1 and upstream of the molding area A3, and is more contaminated than the molding area A3 but less contaminated than the oven area A1.

[0020] The preform conveying mechanism 40 conveys the preforms P inserted through the entrance 21 to the blow molding turret 22, and as shown in Figure 1, it is equipped with a conveying machine 41 that conveys the preforms P mainly in the oven area A1, and multiple turrets 42 that convey the preforms P removed from the oven area A1 toward the blow molding turret 22.

[0021] The turrets 42 transport the preforms P in the transfer area A2 and the molding area A3, and each turret 42 has a plurality of grippers that grip the outer periphery of the preforms P. It is desirable to sterilize the gripping portions of the grippers by irradiating them with UV light or using a disinfectant.

[0022] The transport posture of the preform P by the preform transport mechanism 40 may be any posture, such as upright, inverted (i.e., downward facing with the mouth portion P2 of the preform P facing downward), or horizontal (i.e., horizontal facing with the mouth portion P2 of the preform P facing to the side).

[0023] The aseptic molding device 20 is configured to perform a sterilization process using a container sterilization device 50 or the like when the contents are filled in the filling device 60, so that the container is in a commercially sterile state (i.e., a state in which all microorganisms harmful to public health that may grow in the beverage under normal non-refrigerated storage and distribution conditions have been killed).

[0024] In this embodiment, the sterilization process by the container sterilization device 50 etc. is configured so that sterilization of the container is completed only by preform sterilization at the preform stage before the container is molded by aseptic blow molding, without performing sterilization at the container stage after aseptic blow molding (without requiring sterilization at the container stage) (more specifically, in this embodiment, sterilization is completed by the time of transfer area A2, and the sterilized preform P is transported to molding area A3). In other words, the container is configured so that the preform sterilization process at the preform stage alone will bring the container to a commercially sterile state, and in further other words, the preform sterilization process at the preform stage alone is capable of sterilizing the bacteria to be sterilized (on the entire outer surface including the inner and outer surfaces of the preform P) (bacteria that can grow in the contents to be filled into the container, such as mold, general bacteria, spore-forming bacteria, etc.). The bactericidal effect (bactericidal capacity, D) is expressed by the formula bactericidal effect (D) = LOG ((initial number of bacteria) / (number of surviving bacteria)). For example, if the number of bacteria is reduced from 100 to 10, LOG (100 / 10) = 1D.

[0025] The container sterilization device 50 is configured to sterilize the inner surface (the inner surface of the body portion P1 and the mouth portion P2) and the outer surface (the outer surface of the body portion P1 and the mouth portion P2) of the preform P in an area (in this embodiment, the transfer area A2) downstream of the oven area A1 and upstream of the blow molding turret 22, and as shown in FIG. 1, CO ２ The apparatus includes a laser irradiator 51 as a laser irradiation means for irradiating a laser, a UV light irradiator 52 as a UV light irradiation means for irradiating UV light onto the container surface, and a heating means (in this embodiment, an oven mechanism 30) that is arranged upstream of or at the same location as the laser irradiator 51 and heats the area of ​​the container surface to be sterilized. ２ A laser is a type of gas laser, and this CO ２ Carbon dioxide lasers use a mixture of carbon dioxide, nitrogen, and helium. A discharge current is passed through this gas mixture to produce a laser beam.

[0026] As shown in FIG. 1, the laser irradiator 51 is located in an area (transfer area A2 in this embodiment) downstream of the oven area A1 and upstream of the blow molding turret 22, and irradiates CO 2 onto the container surface of the preform P while it is being transported by the turret 42. ２ The laser irradiator 51 sterilizes the container surface of the preform P by irradiating it with a laser. As shown in FIG. 2, the laser irradiator 51 includes a laser oscillator 51 a and a CO radiator 51 b. ２ The laser irradiator 51 (and UV light irradiator 52) may be installed in the oven area A1 or upstream of the oven area A1. Alternatively, the laser irradiator 51 (and UV light irradiator 52) may be installed downstream of the blow molding turret 22 to irradiate the molded container with CO 2 . ２ Sterilization may be performed by irradiating with a laser.

[0027] 1, in an area (transfer area A2 in this embodiment) downstream of the oven area A1 and upstream of the blow molding turret 22, the UV light irradiator 52 sterilizes the container surface of the preform P by supplying a sterilizing fluid to the container surface of the preform P while it is being transported by the turret 42. Here, the "UV light" referred to in this specification includes ordinary UV light using a UV lamp (including a low-pressure mercury lamp), a xenon lamp (a xenon flash lamp, a xenon arc lamp), a UV-LED, or the like as a light source (UV light source 52a), as well as UV lasers such as UV laser light obtained by converting a YAG (Nd:YAG) laser, which is a solid-state laser, to a UV wavelength using wavelength conversion technology, and UV laser light generated using an excimer laser, which is a gas laser, as a light source, but is not limited to these. 2, the UV light irradiator 52 has an irradiation unit 51b made up of optical elements such as lenses, mirrors, beam expanders, and beam shapers for irradiating UV light emitted from a UV light source 52a. The irradiation unit 51b is not essential, and UV light may be irradiated directly from the UV light source 52a.

[0028] The heating means is performed before or simultaneously with the laser irradiation process by the laser irradiator 51 (and the UV light irradiation process by the UV light irradiator 52), and heats the area to be sterilized on the container surface so that the area is heated during the laser irradiation process (and the UV light irradiation process). In this embodiment, the oven mechanism 30 described above functions as the heating means. Note that the specific form of the heating means is not limited to the above, and the heating means may also be constituted by a heating heater or a supplier that supplies hot water, steam, hot air, etc., provided separately from the oven mechanism 30. In this case, the heating temperature of the area to be sterilized can be set as appropriate, for example, to 60°C or higher, 80°C or higher, 100°C or higher, etc.

[0029] The filling device 60 is installed downstream of the aseptic molding device 20, and as shown in Figure 1, is equipped with a filling section 61 as a filling means for filling the contents into the container, and a capping section 62 located downstream of the filling section 61 for attaching a sterilized cap to the mouth of the container.

[0030] Each process in filling apparatus 60 is performed in a chamber the interior of which is maintained in a sterile state. The sterile state of the containers is also maintained in the section in which the containers are transported between aseptic molding apparatus 20 and filling apparatus 60. In other words, the sterile state of the containers is maintained throughout the entire section from when the containers are aseptically blow-molded by blow molding turret 22 to when the contents are aseptically filled into the containers in filling section 61. In this embodiment, the entire section is covered by a chamber, thereby maintaining the sterile state of the containers throughout this section.

[0031] Next, a container sterilization method using the container sterilization device 50 of this embodiment will be described below.

[0032] First, the container sterilization method of this embodiment is a method of sterilizing a container by heating the container surface before or simultaneously with the laser irradiation treatment. ２ The process includes a laser irradiation process in which a laser is irradiated, and a UV light irradiation process in which UV light is irradiated onto the container surface.

[0033] The laser irradiation process is carried out by a laser irradiator 51, which applies CO to the container surface (in this embodiment, the entire surface including the inner and outer surfaces of the preform P). ２ The laser is irradiated on the path between the inlet 21 of the aseptic filling equipment and the filling section 61 where the filling process is carried out.

[0034] The UV light irradiation treatment is carried out by applying CO to the container surface (in this embodiment, the entire surface including the inner and outer surfaces of the preform P) using a UV light irradiator 52. ２ The UV light irradiation process is performed on the path between the inlet 21 of the aseptic filling equipment and the filling section 61 where the filling process is carried out. It is preferable to irradiate a UV laser in the UV light irradiation process.

[0035] As shown in FIG. 2, the CO ２ It is preferable to set the laser irradiation area and the UV light irradiation area on the container surface in the UV light irradiation treatment so as to overlap (at least partially). As a specific embodiment of the laser irradiation treatment and the UV light irradiation treatment, as shown in Figure 2(a), an irradiation section 51b of the laser irradiator 51 and an irradiation section 52b of the UV light irradiator 52 may be provided separately, and the respective irradiation areas may overlap. ２ The irradiation areas may be overlapped by mixing the laser and the UV laser and irradiating them from the same irradiation units 51b and 52b. Alternatively, the UV light may be directly irradiated from the UV light source 52a without using the irradiation unit 52b of the UV light irradiator 52. Here, the reference numeral 53 shown in FIG. ２ The symbol Lc in FIG. 2 indicates a mixer for mixing a CO laser and a UV laser. ２ The symbol Lu in FIG. 2 denotes a UV laser.

[0036] In the example shown in FIG. ２ Although the laser irradiation and UV light irradiation processes have been described as being performed simultaneously, ２ The laser irradiation and UV light irradiation processes were performed at different timings (CO ２ The laser irradiation may be performed before or after the laser irradiation.

[0037] In addition, the laser irradiation treatment and UV light irradiation treatment to be performed on the preform after the heat treatment (on both the inner and outer surfaces of the preform P, or only on the inner or outer surface of the preform P) may be performed by CO irradiation to the mouth portion P2 of the preform. ２ Integrated laser light intensity (mJ / cm ２ ) is the CO ２ Integrated laser light intensity (mJ / cm ２ ), and / or the integrated amount of UV light (mJ / cm 2 ) applied to the mouth portion P2 of the preform ２ ) is the cumulative amount of UV light (mJ / cm ) applied to the body P1 of the preform. ２ ) is preferably set to be larger than

[0038] In addition, in the laser irradiation process, CO having a wavelength in the 9 μm band (center wavelength 9.0 to 9.9 μm) ２ It is preferable to irradiate the substrate with a laser. In addition, in the laser irradiation process, CO ２ It is preferable to irradiate the container with a laser. This can significantly reduce the time required for the sterilization process of the container. The irradiation time here refers to the time required for the area to be sterilized to be exposed to CO ２ In addition, in the laser irradiation process, in order to obtain a good sterilization effect while avoiding damage to the container surface that is the irradiation target, the CO ２ The cumulative laser light intensity is 1600 mJ / cm ２ or more and 30,000 mJ / cm ２ CO ２ In the laser irradiation process, CO 2 is preferably used in either continuous wave or pulse wave form. ２ A laser may be irradiated.

[0039] The heat treatment is performed by heating the area to be sterilized on the container surface by laser irradiation treatment using a heating means, and in this embodiment, the preform P is heated to the molding temperature during the container molding treatment by an oven mechanism 30 as the heating means. Note that the heat treatment is preferably set so that the area to be sterilized on the container surface is heated to a temperature of 120°C or higher during the laser irradiation treatment performed on the preform P after the heat treatment.

[0040] Next, CO ２ A test conducted to confirm the sterilization effect of laser irradiation will be described with reference to FIG.

[0041] In this test, first, a 1.7 × 10 ３ cfu of spore-forming bacteria (Bacillus atrophaeus spores) and 1.2 × 10 ３ After attaching cfu of mold (Aspergillus niger conidia), the substrate was dried in a clean room to prepare a substrate inoculated with spore-forming bacteria and mold.

[0042] Then, the prepared substrate was subjected to CO ２ After irradiating the substrate with a laser, the number of surviving bacteria on the substrate was measured by the following standard method. Measurement method of surviving bacteria count: The substrate, sterilized surfactant aqueous solution, and sterilized beads were placed in a sterilized test tube, and the test tube was sealed with a sterilized cap. The test tube was shaken to extract surviving bacteria in the surfactant aqueous solution, which were then suspended in a sterilized dilution solution, and the number of bacteria was measured on a standard agar medium by the membrane filtration method for each dilution ratio. The medium was cultured at 35°C for one week, and the number of colonies that appeared according to the dilution ratio was counted to determine the number of surviving bacteria. Note that the CO on the substrate surface was ２ The diameter of the laser irradiation spot was approximately 22 mm, and the "Φ5 output (W)" shown in Figure 3 was the output (W) of the laser oscillator during the test, measured as the output (W) of the portion irradiated onto a circular area with a diameter of 5 mm where the bacteria was inoculated. ２During laser irradiation, the irradiated area of ​​the substrate was heated by a heater so that it was 120°C. ２ The laser is continuous wave, and the output is adjusted by PWM control (frequency 5 kHz). ２ The laser is a pulse wave with a frequency of 1 kHz. ２ The wavelength of the laser is in the 9 μm band (9.3 μm), and the CO ２ The wavelength of the laser is in the 10 μm band (10.6 μm).

[0043] In this test, an optical system was configured using a laser oscillator, an irradiation lens as an irradiation unit, etc. The "Φ5 output (W)" was measured using a power meter (UP55N-300F-H12-D0) manufactured by Gentec.

[0044] From the results of the above tests, the following was found.

[0045] That is, CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of 0.02 seconds or more and 0.05 seconds or less, and the irradiation energy is 1600 mJ / cm ２ or more (more preferably 3310 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of 0.05 seconds or more and 0.075 seconds or less, and the output is 3310 mJ / cm ２ or more (more preferably 3820 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of more than 0.075 seconds and less than 0.1 seconds, and the irradiation energy is 3820 mJ / cm ２ or more (more preferably 6621 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２When the laser wavelength is in the 9 μm band, the irradiation time is in the range of more than 0.1 seconds and less than 0.2 seconds, and the irradiation time is 6621 mJ / cm ２ or more (more preferably 7130 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of more than 0.2 seconds and less than 0.5 seconds, and the irradiation energy is 7130 mJ / cm ２ or more (more preferably 7894 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of more than 0.5 seconds and less than 1.0 seconds, and the output is 7894 mJ / cm ２ or more (more preferably 10186 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 10 μm band, the irradiation time is in the range of 0.05 seconds or more and 1.0 seconds or less, and the output is 5093 mJ / cm ２ or more (more preferably 10200 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band and the substrate is heated, the irradiation time is in the range of 0.005 seconds or more and 0.01 seconds or less, and the irradiation intensity is 400 mJ / cm ２ or more (more preferably 662 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band and the substrate is heated, the irradiation time is in the range of 0.01 seconds or more and 0.03 seconds or less, and the output is 662 mJ / cm ２ or more (more preferably 1986 mJ / cm ２ It was found that a good sterilizing effect on mold can be obtained when the CO ２ When the laser wavelength is in the 9 μm band and the substrate is heated, the irradiation time is in the range of 0.03 seconds or more and 0.05 seconds or less, and the output is 1986 mJ / cm ２or more (more preferably 3310 mJ / cm ２ Therefore, even if the irradiation time is set to 1 second or less (0.025 seconds or more without heating the substrate, and 0.005 seconds or more with heating the substrate), a good sterilization effect on mold can be obtained. ２ It was found that mold can be sterilized by appropriately setting the laser output.

[0046] Also, CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of 0.05 seconds or more and 0.075 seconds or less, and the output is 4966 mJ / cm ２ It was found that a good bactericidal effect against spore-forming bacteria was obtained when the CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of more than 0.075 seconds and less than 0.1 seconds, and the output is 4966 mJ / cm ２ or more (more preferably 6621 mJ / cm ２ It was found that a good bactericidal effect against spore-forming bacteria was obtained when the CO ２ When the laser wavelength is in the 9 μm band, the irradiation time is in the range of more than 0.1 seconds and less than 1.0 seconds, and the irradiation energy is 6621 mJ / cm ２ or more (more preferably 10186 mJ / cm ２ It was found that a good bactericidal effect against spore-forming bacteria was obtained when the CO ２ When the laser wavelength is in the 10 μm band, the irradiation time is in the range of 0.05 seconds or more and 1.0 seconds or less, and the output is 7639 mJ / cm ２ Therefore, even if the irradiation time is set to 1 second or less (0.05 seconds or more), a good sterilization effect on spore-forming bacteria can be obtained. ２ It was found that spore-forming bacteria can be sterilized by appropriately setting the laser output.

[0047] Furthermore, a comparison between A-7 and A-9 revealed that the sterilization effect against spore-forming bacteria was improved when the substrate was heated.

[0048] It was also found that whether the wave was continuous or pulsed did not have a significant effect on the sterilization effect.

[0049] Also, CO ２ It was found that the higher the laser output (Φ5 output) and the shorter the irradiation time, the smaller the integrated light dose required for sterilization.

[0050] In addition, CO ２ The mechanism by which lasers exert the excellent sterilization effect described above is not entirely clear. However, the absorbance of spore-forming bacteria (Bacillus atrophaeus), mold (Aspergillus niger), and PET resin against the wavelength of light shown in Figure 5 indicates that CO ２ In the wavelength band of the laser, especially in the 9 μm band, spore-forming bacteria, mold, and PET resin all show high absorbance. ２ It is believed that the excellent sterilizing effect is achieved because the PET resin is heated by absorbing the laser light, destroying the DNA, and indirectly heating the bacteria cells as well. The absorbance was measured using a Fourier transform infrared spectrophotometer (JASCO Corporation, FT / IR6700) using the Kbr tablet method.

[0051] In this embodiment, the CO ２ By combining a laser irradiation process in which a laser is irradiated and a UV light irradiation process in which UV light is irradiated onto the container surface, it is possible to reduce the amount of UV light irradiation alone or CO ２ Compared to attempting to sterilize both spore-forming bacteria and mold using only laser irradiation, it is possible to effectively sterilize both spore-forming bacteria and mold in a short time with low output, and also to simplify the device configuration of each irradiator.

[0052] That is, if one were to try to obtain a sterilization effect equivalent to 6D for both spore-forming bacteria and molds by UV light irradiation alone, as can be seen from the graph shown in FIG. 4, 77 mJ / cm is required to sterilize spore-forming bacteria. ２ UV light (UV laser) irradiation of 619 mJ / cm is sufficient for sterilizing mold. ２ UV light (UV laser) irradiation is required. ２ Combined with laser irradiation, CO is used for mold. ２ If sterilization is performed by laser irradiation, UV light is 77 mJ / cm ２ Irradiation of 1000μg / m² will be sufficient.

[0053] The graph shown in Fig. 4(a) is an estimate of the sterilization effect of a UV laser based on the integrated light intensity value (value obtained in a test) of a UV laser required to achieve a sterilization effect of 2.0 D on spore-forming bacteria, and the graph shown in Fig. 4(b) is an estimate of the sterilization effect of a UV laser based on the integrated light intensity value (value obtained in a test) of a UV laser required to achieve a sterilization effect of 2.5 D on mold. ２ cfu of spore-forming bacteria (Bacillus atrophaeus spores) and 4.3 × 10 ３ A substrate inoculated with spore-forming bacteria and mold was prepared by attaching mold (Aspergillus niger conidia) of 10 ... ２ It is estimated that UV light (UV laser) irradiation of 619 mJ / cm is required to achieve a sterilization effect equivalent to 6D for mold using UV laser irradiation. ２ It can be seen that it is estimated that UV light (UV laser) irradiation of 10 ...

[0054] As can be seen from the sterilization effects shown in Figures 3 and 4, UV light (UV laser) irradiation is excellent in sterilizing spore-forming bacteria, and CO ２ Since laser irradiation tends to be excellent at killing mold, from the viewpoint of suppressing the total output, it is preferable to set the laser irradiation process and the UV light irradiation process so that the mold killing ability (D) of the laser irradiation process is higher than the mold killing ability (D) of the UV light irradiation process. Also, from the same viewpoint, it is preferable to set the laser irradiation process and the UV light irradiation process so that the spore-forming bactericidal ability (D) of the laser irradiation process is lower than the spore-forming bactericidal ability (D) of the UV light irradiation process.

[0055] Also, CO ２ By adopting sterilization by laser irradiation and UV light irradiation, sterilization by disinfectant is not required, or even if disinfectant sterilization is used in combination, the amount of disinfectant used can be reduced, thereby reducing the risk of disinfectant remaining in the molded container.

[0056] In addition, the present invention further includes a heating process that is carried out before or simultaneously with the laser irradiation process, and in this heating process, the sterilization effect of the sterilization area on the container surface can be further improved by heating the sterilization area on the container surface using the laser irradiation process.

[0057] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design modifications can be made without departing from the scope of the present invention as set forth in the claims. Furthermore, the respective configurations of the above-described embodiments and the modified examples described below may be arbitrarily combined to form a container sterilization method or a container sterilization device 50.

[0058] Furthermore, in the above-described embodiment, the container sterilization method (container sterilization device 50) was described as being configured to sterilize the container surface of the preform P, which is a container preform, but the specific aspects of the aseptic filling method (aseptic filling system 10) are not limited to the above, and the container surface of the container after molding may also be sterilized.

[0059] Furthermore, in the above-described embodiment, the container preform is the preform P and the container is a PET bottle. However, the specific aspects of the container preform and the container are not limited to this. For example, the container may be a resin-coated can or a painted can. The container preform may be a sheet material (for example, a sheet material in which the surface of a paper base material is coated with a synthetic resin, or a sheet material formed as a resin film), and the container may be a sheet material container (for example, a paper pack or a pouch) obtained by molding the sheet material. In this case, too, the laser irradiation process and the UV light irradiation process are performed on the sheet material or the like as the container preform or the sheet material container or the like as the container. In this case, the laser irradiation process and the UV light irradiation process may be performed on the CO ２The irradiation spots of the laser and UV light are set in a horizontally elongated shape in which the width in a direction perpendicular to the conveying direction is wider than the vertical width in the conveying direction of the sheet material as the container preform, and CO ２ Laser and UV light may also be used.

[0060] In addition, when the container surface is made of (or coated with) synthetic resin such as PET (polyethylene terephthalate), PP (polypropylene), or PE (polyethylene), CO ２ To avoid damage to the container surface caused by the laser, CO ２ The cumulative laser light intensity is 30,000 mJ / cm ２ CO ２ Preferably, a laser is used.

[0061] Furthermore, in the above-described embodiment, the container sterilization device 50 has been described as including the laser irradiator 51, the UV light irradiator 52, etc., but the container sterilization device 50 may also include other sterilization devices as components thereof, such as a sterilization device that sterilizes by supplying a sterilizing fluid such as hydrogen peroxide (aqueous hydrogen peroxide solution), peracetic acid (aqueous peracetic acid solution), or water (hot water, steam) to the container surface of a container or a container preform, a sterilization device that sterilizes by irradiating the container surface with an electron beam, or a dust remover that removes dust adhering to the preform P. Note that when water (hot water, steam) is used as the sterilizing fluid, the risk of the sterilant remaining in the molded container can be eliminated.

[0062] In the above-described embodiment, the laser irradiation process uses CO 2 having a wavelength in the 9 μm band (central wavelength of 9.0 to 9.9 μm, such as 9.3 μm or 9.6 μm). ２ Although the description has been given assuming that a laser is used for irradiation, other wavelengths, for example, CO in the 10 μm band (central wavelengths of 10.2 μm, 10.6 μm, etc., central wavelengths of 10.0 to 10.9 μm) may also be used. ２ A laser may be irradiated.

[0063] The wavelength of the UV light irradiated in the UV light irradiation process is preferably set to a center wavelength of 240 to 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 (UV laser light generated by wavelength conversion technology using a YAG (Nd:YAG) laser) or a center wavelength of 248 nm (UV laser light generated using an excimer laser as a UV light source). Furthermore, it is preferable to set the center wavelength to 254 nm for a UV lamp (low-pressure mercury lamp), 240 to 280 nm for a xenon flash lamp, and 265 nm for a UV-LED.

[0064] In the above-described embodiment, the entire container surface of the container or container preform, including the inner and outer surfaces, is coated with CO ２ Although the description has been given of irradiation with laser and UV light, it is also possible to irradiate only a portion of the container surface (for example, only the inner surface, only the outer surface, only the inner surface of the mouth, etc.) with CO . ２ Laser and UV light may also be used.

[0065] In the above-described embodiment, CO ２ Although the explanation has been given of sterilizing the container surface by irradiating it with a laser, ２ Instead of a laser, a laser with an infrared wavelength (specifically, a laser with a wavelength of 0.78 μm to 1000 μm, including a laser with a near-infrared wavelength, a mid-infrared wavelength, and a far-infrared wavelength) may be used to sterilize the container surface. ２ In addition to lasers, diode lasers, fiber lasers, YAG lasers, YVO ４ Known lasers such as IR lasers and CO lasers may also be used. Compared to known infrared lamps and heaters, infrared wavelength lasers have high directivity and can irradiate the target area with infrared rays in a concentrated manner, resulting in high energy efficiency. In addition, the output rises quickly when irradiation starts, enabling short-term ON-OFF control. Specific aspects of the aseptic filling method and system using infrared wavelength lasers are described in detail in the CO ２ The CO laser described above is used except that a laser of infrared wavelength is used instead of the laser. ２Since it is exactly the same as the aseptic filling method and system using a laser, ２ "CO" in the explanation of the aseptic filling method and system using a laser ２ By replacing "laser" with "laser of infrared wavelength," specific explanation will be omitted.

[0066] The above-mentioned aseptic filling method and system using an infrared wavelength laser can also be described as, but are not limited to, the following supplementary notes. (Supplementary Note 1) A container sterilization method for sterilizing the container surface of a container or a container preform, comprising: a laser irradiation process in which an infrared wavelength laser is irradiated onto the container surface; and a UV light irradiation process in which UV light is irradiated onto the container surface. (Supplementary Note 2) The container sterilization method according to Supplementary Note 1, wherein an area irradiated with an infrared wavelength laser in the laser irradiation process and an area irradiated with UV light in the UV light irradiation process overlap. (Supplementary Note 3) The container sterilization method according to Supplementary Note 1 or Supplementary Note 2, wherein a UV laser is irradiated in the UV light irradiation process. (Supplementary Note 4) The container sterilization method according to Supplementary Note 3, wherein the laser irradiation process and the UV light irradiation process are performed by combining an infrared wavelength laser and a UV laser and irradiating them from the same irradiation unit. (Appendix 5) A container sterilization method according to any one of Appendices 1 to 4, characterized in that the sterilization ability against mold by the laser irradiation treatment is set higher than the sterilization ability against mold by the UV light irradiation treatment. (Appendix 6) A container sterilization method according to any one of Appendices 1 to 5, characterized in that the sterilization ability against spore-forming bacteria by the laser irradiation treatment is set lower than the sterilization ability against spore-forming bacteria by the UV light irradiation treatment. (Appendix 7) A container sterilization method according to any one of Appendices 1 to 6, further comprising a heat treatment carried out before or simultaneously with the laser irradiation treatment, wherein the heat treatment heats the area of ​​the container surface to be sterilized by the laser irradiation treatment. (Appendix 8) A container sterilization method according to any one of Appendices 1 to 6, further comprising a heat treatment of heating a preform as the container preform to a molding temperature when it is molded into a PET bottle as the container, wherein the laser irradiation treatment and the UV light irradiation treatment are carried out on the preform after the heat treatment, and wherein the integrated light amount (mJ / cm) of an infrared wavelength laser on a mouth portion of the preform is ２ ) is the integrated light amount (mJ / cm ) of the infrared wavelength laser to the body of the preform. ２ ) and / or the integrated amount of UV light (mJ / cm ) applied to the mouth of the preform２ ) is the cumulative amount of UV light (mJ / cm ) applied to the body of the preform. ２ (Supplementary Note 9) A container sterilization method according to any one of Supplementary Notes 1 to 7, characterized in that the surface area of ​​a container or a container preform is larger than the surface area of ​​the container. (Supplementary Note 9) A container sterilization device for sterilizing a container surface of a container or a container preform, comprising: a laser irradiation means for irradiating the container surface with a laser having an infrared wavelength; and a UV light irradiation means for irradiating the container surface with UV light.

[0067] DESCRIPTION OF SYMBOLS 10: Aseptic filling system 20: Aseptic molding device 21: Inlet section 22: Blow molding turret 30: Oven mechanism 31: Oven chamber 32: Heating heater 40: Preform conveying mechanism 41: Conveyor 42: Turret 50: Container sterilization device 51: Laser irradiator (laser irradiation means) 51a: Laser oscillator 51b: Irradiation section 52: UV light irradiator (UV light irradiation means) 52a: UV light source 52b: Irradiation section 53: Mixer 60: Filling device 61: Filling section 62: Capping section P: Preform (container preform) P1: Body section of preform P2: Mouth section of preform A1: Oven area A2: Transfer area A3: Molding area Lc: CO ２ Laser Lu... UV light

Claims

1. A method for sterilizing the surface of a container or a preform of a container, the method comprising: irradiating the surface of the container with a CO ２ laser irradiation treatment of irradiating the surface of the container with a CO laser, and a UV light irradiation treatment of irradiating the surface of the container with UV light. The method for sterilizing a container is characterized by including these treatments.

2. The CO in the laser irradiation treatment ２ The container sterilization method according to claim 1, wherein the irradiation area of the laser and the irradiation area of the UV light in the UV light irradiation treatment overlap each other.

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

4. The laser irradiation treatment and the UV light irradiation treatment are carried out by mixing a CO ２ laser and a UV laser and irradiating from the same irradiation part, and the container sterilization method according to claim 3 is characterized in that it is carried out.

5. The container sterilization method according to claim 1, wherein the sterilization ability against mold by the laser irradiation treatment is set higher than the sterilization ability against mold by the UV light irradiation treatment.

6. The container sterilization method according to claim 1, wherein the sterilization ability against spore bacteria by the laser irradiation treatment is set lower than the sterilization ability against spore bacteria by the UV light irradiation treatment.

7. The container sterilization method according to claim 1, further comprising a heat treatment performed before or simultaneously with the laser irradiation treatment, wherein in the heat treatment, the sterilization target area on the surface of the container by the laser irradiation treatment is heated.

8. Further include a heat treatment of heating the preform as the container preform to the molding temperature when molding it into a PET bottle as the container, and the laser irradiation treatment and the UV light irradiation treatment are performed on the preform after the heat treatment, and CO to the mouth of the preform ２ The integrated light amount of the laser (mJ / cm ２ ) is the integrated light amount of CO to the body of the preform ２ The integrated light amount of the laser (mJ / cm ２ ), and / or the integrated light amount of the UV light to the mouth of the preform (mJ / cm ２ ) is the integrated light amount of the UV light to the body of the preform (mJ / cm ２ ), and the container sterilization method according to claim 1 is characterized in that it is larger.

9. A container sterilization device for sterilizing the surface of a container or a preform of a container, wherein CO ２ laser irradiation means for irradiating the surface of the container with a CO laser, and UV light irradiation means for irradiating the surface of the container with UV light, the container sterilization device being characterized by including these means.

10. A container sterilization method for sterilizing the surface of a container or a container preform, comprising: a laser irradiation treatment for irradiating the surface of the container with a laser having an infrared wavelength; and a UV light irradiation treatment for irradiating the surface of the container with UV light.

11. A container sterilization apparatus for sterilizing the surface of a container or a container preform, comprising: a laser irradiation means for irradiating the surface of the container with a laser having an infrared wavelength; and a UV light irradiation means for irradiating the surface of the container with UV light.

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