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

[Technical Field]

[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. [Background technology]

[0002] BACKGROUND ART 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). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-202284 Summary of the Invention [Problem to be solved by the invention]

[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. [Means for solving the problem]

[0006] One 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 in which a CO2 laser is irradiated onto the container surface, and a UV light irradiation process in which UV light is irradiated onto the container surface. 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 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. In addition, one aspect of the container sterilization device of the present invention is a container sterilization device that sterilizes the container surface of a container or a container preform, and solves the above-mentioned problem by including a laser irradiation means that irradiates the container surface with a CO2 laser and a UV light irradiation means that irradiates the container surface with UV light. Another aspect of the container sterilization device of the present invention is a container sterilization device that sterilizes the container surface of a container or a container preform, and solves the above-mentioned problem by including a laser irradiation means that irradiates the container surface with a laser of an infrared wavelength, and a UV light irradiation means that irradiates the container surface with UV light.

[0007] In either the container sterilization method or the container sterilization device, the region irradiated with the CO2 laser in the laser irradiation process and the region irradiated with the UV light in the UV light irradiation process may overlap. In either the container sterilization method or the container sterilization device, the UV light irradiation process may involve irradiating with a UV laser. In either the container sterilization method or the container sterilization device, the laser irradiation process and the UV light irradiation process may be performed by mixing a CO2 laser and a UV laser and irradiating them from the same irradiation unit. In either the container sterilization method or the container sterilization device, the sterilization ability against mold by the laser irradiation process may be set to be higher than the sterilization ability against mold by the UV light irradiation process. In either the container sterilization method or the container sterilization device, the sterilization ability of the laser irradiation treatment against spore-forming bacteria may be set to be lower than the sterilization ability of the UV light irradiation treatment against spore-forming bacteria. Either of the above container sterilization methods or container sterilization devices may further include a heating treatment carried out before or simultaneously with the laser irradiation treatment, in which the area to be sterilized on the surface of the container is heated by the laser irradiation treatment. Either the container sterilization method or the container sterilization device further includes a heat treatment for heating the preform as the container preform to a molding temperature when the preform is molded into the 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 the integrated light amount (mJ / cm) of the CO2 laser on the mouth portion of the preform is 2 ) is the cumulative light intensity (mJ / cm) of the CO2 laser on the body of the preform. 2 ), 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 . [Effects of the Invention]

[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. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing an aseptic filling system equipped with a container sterilization device according to one embodiment of the present invention. [Figure 2] 1A and 1B are explanatory diagrams showing examples of CO2 laser and UV light irradiation modes. [Figure 3] An explanatory diagram showing the results of a test to confirm the sterilization effect of CO2 laser irradiation. [Figure 4] FIG. 1 is an explanatory diagram showing the sterilization effect of UV light irradiation. [Figure 5] A graph showing the absorbance of spore-forming bacteria, mold, and PET resin versus light wavelength. DETAILED DESCRIPTION OF THE INVENTION

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

[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 the 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 device 20 aseptically molds sterilized containers that have been subjected to a sterilization treatment, and as shown in Figure 1, it is equipped with an inlet section 21 into which preforms P, which are preliminary molded container 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] As shown in FIG. 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 sterile air into a preform P that has been heated to the molding temperature during sterile blow molding.

[0016] The molding area A3 where the blow molding turret 22 is installed is covered by a chamber, and a sterile atmosphere and positive pressure are maintained by blowing sterile air that has passed through a HEPA filter from above using an FFU (Fan Filter Unit). In addition, the blow molding turret 22, blow machine, and other equipment installed in the molding area A3 are sterilized down to the ends of the blow piping. Preforms P, which have been sterilized only at the preform stage, are transported to molding area A3 and aseptically blow molded. As a result, aseptic blow molding, which is blow molding performed under sterile conditions, is performed in molding area A3, which eliminates the need to locally create an atmosphere of sterile air or sterilizing gas near the transport path when transporting preforms P or containers after blow molding within molding area A3, and also eliminates the need to sterilize the containers after blow molding.

[0017] The oven mechanism 30 performs a heating process to raise the temperature of the preform P (its 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 multiple heating heaters 32 configured as infrared heaters that raise the temperature of the preform P. The oven mechanism 30 may be provided with a simple cover surrounding 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 the 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 the 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 preforms P from the outer periphery. 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., a downward position with the mouth portion P2 of the preform P facing downward), or horizontal (i.e., a horizontal position 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 containers are 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 formed 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 configured to be able to sterilize the bacteria to be sterilized (bacteria that can grow in the contents to be filled into the container, such as mold, general bacteria, spore-forming bacteria, etc.) (on the entire outer surface including the inner and outer surfaces of the preform P). 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, then 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 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 Figure 1, it is equipped with a laser irradiator 51 as a laser irradiation means that irradiates the container surface of the container or preform P with a CO2 laser, a UV light irradiator 52 as a UV light irradiation means that irradiates the container surface with UV light, and a heating means (in this embodiment, an oven mechanism 30) that is arranged upstream of or in the same location as the laser irradiator 51 and heats the area of ​​the container surface to be sterilized. A CO2 laser is a type of gas laser, and this CO2 (carbon dioxide) laser uses a gas mixture of carbon dioxide, nitrogen, and helium. A discharge current is passed through this mixed gas to produce a laser beam.

[0026] As shown in FIG. 1, the laser irradiator 51 sterilizes the container surface of the preform P by irradiating it with a CO2 laser in an area downstream of the oven area A1 and upstream of the blow molding turret 22 (in this embodiment, the transfer area A2) while the preform P is being transported by the turret 42. As shown in FIG. 2, the laser irradiator 51 has a laser oscillator 51a and an irradiation section 51b consisting of optical elements such as lenses, mirrors, beam expanders, and beam shapers for irradiating the CO2 laser oscillated by the laser oscillator 51a. 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, and the molded containers may be sterilized by irradiating them with a CO2 laser.

[0027] As shown in FIG. 1, 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 in an area downstream of the oven area A1 and upstream of the blow molding turret 22 (in this embodiment, the transfer area A2). Here, the "UV light" referred to in this specification includes, but is not limited to, 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. 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 above-mentioned oven mechanism 30 functions as the heating means. The specific embodiment of the heating means is not limited to the above, and the heating means may 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 appropriately 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 step in the filling device 60 is carried out in a chamber whose interior is maintained in a sterile state. In addition, the sterile state of the container is maintained even in the section where the container is transported between the aseptic molding device 20 and the filling device 60. In other words, the sterile state of the container is maintained throughout the entire section from when the container is aseptically blow-molded by the blow molding turret 22 to when the contents are aseptically filled into the container in the filling section 61. In this embodiment, the sterile state of the container is maintained throughout the entire section by covering the above-mentioned entire section with a chamber.

[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 includes a heating process carried out before or simultaneously with the laser irradiation process, a laser irradiation process in which a CO2 laser is irradiated onto the container surface, and a UV light irradiation process in which UV light is irradiated onto the container surface.

[0033] The laser irradiation process involves irradiating the container surface (in this embodiment, the entire surface including the inner and outer surfaces of the preform P) with a CO2 laser using a laser irradiator 51, and is carried out on the path between the entrance 21 of the aseptic filling equipment and the filling section 61 where the filling process is carried out.

[0034] The UV light irradiation process involves irradiating the container surface (in this embodiment, the entire surface including the inner and outer surfaces of the preform P) with a CO2 laser using a UV light irradiator 52, and is carried out on the path between the entrance 21 of the aseptic filling equipment and the filling section 61 where the filling process is carried out. In the UV light irradiation process, it is preferable to irradiate with a UV laser.

[0035] As shown in FIG. 2, it is preferable to set the CO2 laser irradiation area on the container surface in the laser irradiation process and the UV light irradiation area on the container surface in the UV light irradiation process so that they (at least partially) overlap. As a specific example of the laser irradiation process and the UV light irradiation process, as shown in Fig. 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 irradiation areas may overlap, or as shown in Fig. 2(b), a CO2 laser and a UV laser may be mixed and irradiated from the same irradiation sections 51b and 52b, so that the irradiation areas overlap. Also, UV light may be irradiated directly from the UV light source 52a without using the irradiation section 52b of the UV light irradiator 52. Here, reference numeral 53 shown in FIG. 2 denotes a mixer that mixes the CO2 laser and the UV laser, reference numeral Lc shown in FIG. 2 denotes the CO2 laser, and reference numeral Lu shown in FIG. 2 denotes the UV laser.

[0036] In the example shown in FIG. 2, the CO2 laser irradiation and UV light irradiation processes are described as being performed simultaneously, but the CO2 laser irradiation and UV light irradiation processes may be performed at different times (before or after the CO2 laser irradiation).

[0037] The laser irradiation treatment and UV light irradiation treatment to be performed on the preform after the heat treatment are carried out (on both the inner and outer surfaces of the preform P, or only on the inner or outer surface of the preform P) by the integrated light amount (mJ / cm) of the CO2 laser to the opening part P2 of the preform. 2 ) is the cumulative light intensity (mJ / cm ) of the CO laser on the body P1 of the preform. 2 ), and / or the integrated amount of UV light (mJ / cm 2 ) is the cumulative amount of UV light (mJ / cm 2 ) is preferably set to be larger than

[0038] In addition, in the laser irradiation process, it is preferable to irradiate with a CO2 laser having a wavelength in the 9 μm band (center wavelength of 9.0 to 9.9 μm). In addition, it is preferable to irradiate the CO2 laser for a time of 1 second or less during the laser irradiation process. This significantly reduces the time required for the container sterilization process. The irradiation time here refers to the time the area to be sterilized receives the CO2 laser light. 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 integrated light intensity of the CO2 laser on the sterilization target area of ​​the container surface is set to 1600 mJ / cm 2 or more and 30,000mJ / cm 2 It is preferable to irradiate with a CO2 laser so that the following occurs: In addition, in the laser irradiation process, the CO2 laser may be irradiated in either a continuous wave or pulse wave form.

[0039] The heating process involves heating the area of ​​the container surface to be sterilized by laser irradiation using a heating means, and in this embodiment, the preform P is heated to the molding temperature during the container molding process using an oven mechanism 30 as the heating means. 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 carried out on the preform P after the heat treatment.

[0040] Next, a test conducted to confirm the sterilization effect of CO2 laser irradiation will be explained with reference to FIG.

[0041] In this test, 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] The prepared substrate was irradiated with a CO2 laser under the conditions shown in Figure 3, and the number of surviving bacteria on the substrate was then measured using the following standard method. Method for measuring surviving bacterial count: After placing the above substrate, sterilized surfactant aqueous solution, and sterilized beads in a sterilized test tube, the test tube was sealed with a sterilized cap, and 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 counted by the membrane filtration method on a standard agar medium at each dilution ratio. The medium was stored 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. The CO2 laser irradiation spot diameter on the substrate surface was approximately 22 mm, and the "Φ5 output (W)" shown in Figure 3 was the measured output (W) of the laser oscillator during the test that was irradiated onto a circular area with a diameter of 5 mm where the bacteria had been inoculated. In addition, the substrates A-9 to A-12 were heated by a heater so that the irradiated area of ​​the substrate was heated to 120°C during CO2 laser irradiation. The CO2 laser irradiated in A-1 to A-12 is a continuous wave, and the output is adjusted by PWM control (frequency 5 kHz). The CO2 laser irradiated in B-1 to B-3 and C-1 to C-7 is a pulse wave, and the frequency is 1 kHz. The wavelength of the CO2 laser irradiated at A-1 to 12 and B-1 to 3 is in the 9 μm band (9.3 μm), and the wavelength of the CO2 laser irradiated at C-1 to 7 is in the 10 μm band (10.6 μm).

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

[0044] The results of the above tests revealed the following:

[0045] That is, when the wavelength of the CO2 laser 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 output is 1600 mJ / cm 2 or more (more preferably 3310 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 3820 mJ / cm 2 or more (more preferably 6621 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 output is 6621 mJ / cm 2 or more (more preferably 7130 mJ / cm 2It was found that when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 output is 7130 mJ / cm 2 or more (more preferably 7894 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 laser output is 400 mJ / cm 2 or more (more preferably 662 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser 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 when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. In addition, when the wavelength of the CO2 laser is in the 9 μm band and the substrate is heated, the irradiation time is between 0.03 seconds and 0.05 seconds, and the output is 1986 mJ / cm 2 or more (more preferably 3310 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect on mold can be obtained. Therefore, it was found that even if the irradiation time was set to 1 second or less (0.025 seconds or more without substrate heating, 0.005 seconds or more with substrate heating), mold could be sterilized by appropriately setting the output of the CO2 laser.

[0046] In addition, when the wavelength of the CO2 laser 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 when the above conditions are met, a good bactericidal effect against spore-forming bacteria can be obtained. In addition, when the wavelength of the CO2 laser 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 radiation intensity is 4966 mJ / cm 2 or more (more preferably 6621 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect against spore-forming bacteria can be obtained. In addition, when the wavelength of the CO2 laser 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 output is 6621 mJ / cm 2 or more (more preferably 10186 mJ / cm 2 It was found that when the concentration of the solution is 100% or more, a good bactericidal effect against spore-forming bacteria can be obtained. In addition, when the wavelength of the CO2 laser 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 It was found that when the above conditions are met, a good bactericidal effect against spore-forming bacteria can be obtained. Therefore, it was found that even if the irradiation time was set to 1 second or less (0.05 seconds or more), it was possible to sterilize spore-forming bacteria by appropriately setting the output of the CO2 laser.

[0047] Furthermore, a comparison of A-7 and A-9 revealed that the bactericidal effect on 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] It was also found that the higher the CO2 laser output (Φ5 output) and the shorter the irradiation time, the smaller the cumulative light intensity needed for sterilization.

[0050] Although the mechanism by which CO2 lasers exert the excellent sterilization effect described above is not entirely clear, Figure 5 shows the absorbance of spore-forming bacteria (Bacillus atrophaeus), mold (Aspergillus niger), and PET resin at different wavelengths of light. The spore-forming bacteria, mold, and PET resin all exhibit high absorbance in the CO2 laser wavelength range, particularly in the 9 μm band. The bacteria absorb the CO2 laser light and are directly heated, destroying their DNA. The PET resin is also heated by the laser light, indirectly heating the bacteria, which is thought to result in an excellent sterilization effect. Absorbance was measured using a Fourier transform infrared spectrophotometer (JASCO Corporation FT / IR6700) using the KBR tablet method.

[0051] In this embodiment obtained in this manner, by combining a laser irradiation process in which a CO2 laser is irradiated onto the container surface with a UV light irradiation process in which UV light is irradiated onto the container surface, it is possible to effectively sterilize both spore-forming bacteria and mold with small output and in a short time compared to attempts to sterilize both spore-forming bacteria and mold using only UV light irradiation or only CO2 laser irradiation, and it is also possible 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 using UV light alone, as can be seen from the graph in Figure 4, 77 mJ / cm would be required to sterilize spore-forming bacteria. 2 UV light (UV laser) irradiation of 619 mJ / cm is sufficient for sterilizing mold. 2 If CO2 laser irradiation is used in combination with UV light (UV laser) to sterilize mold, the UV light will be 77 mJ / cm 2 Irradiation of 1000μg / m² will be sufficient.

[0053] The graph shown in Figure 4(a) is an estimate of the bactericidal effect of UV lasers based on the cumulative light intensity value (value obtained in tests) of UV lasers required to achieve a bactericidal effect of 2.0D on spore-forming bacteria, and the graph shown in Figure 4(b) is an estimate of the bactericidal effect of UV lasers based on the cumulative light intensity value (value obtained in tests) of UV lasers required to achieve a bactericidal effect of 2.5D on mold. The above test is carried out by applying 1.4 × 10 2 cfu of spore-forming bacteria (Bacillus atrophaeus spores) and 4.3 × 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. The substrate was then irradiated with a UV laser with a central wavelength of 266 nm, and the number of surviving bacteria on the substrate was then measured using the standard method described above. From the graph in Figure 4, if you try to achieve a sterilization effect equivalent to 6D for spore-forming bacteria with UV laser irradiation, it will be 77 mJ / cm 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 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 superior in sterilizing spore-forming bacteria, and CO2 laser irradiation tends to be superior in sterilizing mold. Therefore, from the perspective of reducing the total output, it is preferable to set the laser irradiation process and the UV light irradiation process so that the sterilization ability (D) against mold by the laser irradiation process is higher than the sterilization ability (D) against mold by the UV light irradiation process. From a similar perspective, it is preferable to set the laser irradiation process and the UV light irradiation process so that the sterilization ability (D) of the laser irradiation process against spore-forming bacteria is lower than the sterilization ability (D) of the UV light irradiation process against spore-forming bacteria.

[0055] In addition, by adopting sterilization using CO2 laser irradiation and UV light irradiation, sterilization using disinfectants 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 method further includes a heating process that is performed 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 defined in the claims. Furthermore, the configurations of the above-described embodiments and the modified examples described below may be arbitrarily combined to form a container sterilization method and 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 described as being the preform P, and the container as being a PET bottle, but the specific aspects of the container preform and the container are not limited to this, and for example, the container may be a resin-coated can or a painted can, or 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 as well, the laser irradiation process and the UV light irradiation process are performed on a sheet material or the like serving as a container preform or a sheet material container or the like serving as a container. In this case, in the laser irradiation process and UV light irradiation process, the irradiation spots of the CO2 laser and UV light may be set to a horizontally elongated shape whose width in a direction perpendicular to the conveying direction is wider than the vertical width in the conveying direction of the sheet material serving as the container preform, and the CO2 laser and UV light may be irradiated onto the sheet material while the sheet material is being conveyed.

[0060] In addition, if the container surface is made of (or coated with) synthetic resin such as PET (polyethylene terephthalate), PP (polypropylene), or PE (polyethylene), the cumulative light intensity of the CO2 laser on the area to be sterilized on the container surface must be 30,000 mJ / cm2 to prevent damage to the container surface by the CO2 laser. 2 It is preferable to irradiate with a CO2 laser so that the following occurs:

[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 processors as components thereof, such as a sterilization processor 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 processor 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] Furthermore, in the above-described embodiment, the laser irradiation process is described as irradiating a CO2 laser 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), but it is also possible to irradiate a CO2 laser having another wavelength, for example, a 10 μm band (central wavelength of 10.0 to 10.9 μm, such as 10.2 μm or 10.6 μm).

[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 of 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 addition, in the above-described embodiment, the CO2 laser and UV light are irradiated onto the entire container surface of the container or container preform, including the inner and outer surfaces. However, the CO2 laser and UV light may be irradiated onto 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.).

[0065] In the above-described embodiment, the container surface is sterilized by irradiating it with a CO2 laser, but instead of a CO2 laser, the container surface may be sterilized by irradiating it with an infrared wavelength laser (specifically, a laser with a wavelength of 0.78 μm to 1000 μm, including lasers with near-infrared wavelengths, mid-infrared wavelengths, and far-infrared wavelengths). In addition to the CO2 laser, known lasers such as a diode laser, fiber laser, YAG laser, YVO4 laser, and CO laser may also be used. Compared to known infrared lamps and heaters, infrared wavelength lasers have high directionality and can irradiate infrared rays intensively on the area to be sterilized, making them highly energy efficient. They also have the advantage of having a fast output rise when irradiation begins, allowing for short-term ON-OFF control. The specific aspects of the aseptic filling method and system using an infrared wavelength laser are exactly the same as the aseptic filling method and system using a CO2 laser described above, except that an infrared wavelength laser is used instead of a CO2 laser. Therefore, the specific explanation will be omitted by replacing "CO2 laser" in the explanation of the aseptic filling method and system using a CO2 laser described above with "infrared wavelength laser."

[0066] Furthermore, the above-mentioned aseptic filling method and system using an infrared wavelength laser can also be described as follows, but is not limited to the following: (Appendix 1) A container sterilization method for sterilizing a container surface of a container or a container preform, comprising: a laser irradiation process of irradiating the surface of the container with a laser having an infrared wavelength; a UV light irradiation treatment for irradiating the surface of the container with UV light; A method for sterilizing a container, comprising: (Appendix 2) 2. A container sterilization method according to claim 1, characterized in that the irradiation area of ​​the infrared wavelength laser in the laser irradiation process and the irradiation area of ​​the UV light in the UV light irradiation process overlap. (Appendix 3) 3. The container sterilization method according to claim 1, wherein the UV light irradiation treatment is performed by irradiating with a UV laser. (Appendix 4) The container sterilization method according to claim 3, characterized in that the laser irradiation process and the UV light irradiation process are carried out by mixing 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 of the laser irradiation treatment against spore-forming bacteria is set lower than the sterilization ability of the UV light irradiation treatment against spore-forming bacteria. (Appendix 7) Further comprising a heat treatment carried out before or simultaneously with the laser irradiation treatment; 7. The container sterilization method according to any one of claims 1 to 6, wherein the heat treatment comprises heating the area to be sterilized on the surface of the container by the laser irradiation treatment. (Appendix 8) The method further includes a heat treatment in which the preform as the container preform is heated to a molding temperature at which the preform is molded into a PET bottle as the container, The laser irradiation treatment and the UV light irradiation treatment are performed on the preform after the heat treatment, The integrated light intensity (mJ / cm) of the infrared wavelength laser on the mouth of the preform 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 preform. 2 ) is the cumulative amount of UV light (mJ / cm ) applied to the body of the preform. 2 ) is characterized by being larger than A method for sterilizing a container according to any one of Supplementary Notes 1 to 7. (Appendix 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 surface of the container with a laser having an infrared wavelength; UV light irradiation means for irradiating the surface of the container with UV light; A container sterilization device comprising: [Explanation of symbols]

[0067] 10. Aseptic Filling System 20... Aseptic molding equipment 21 Entrance 22 Blow molding turret 30 Oven mechanism 31 Oven chamber 32 Heating heater 40 Preform transport mechanism 41 Conveyor 42 Turret 50... Container sterilizer 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 equipment 61 Filling section 62 Capping section P ··· Preform (preformed container) P1: Body of the preform P2: Mouth of preform A1 Oven area A2 Transfer area A3: Molding area Lc...CO2 laser Lu··· UV light

Claims

1. A container sterilization method for sterilizing a container surface of a container or a container preform, comprising: CO ２ a laser irradiation process for irradiating a laser; a UV light irradiation treatment for irradiating the surface of the container with UV light; a heat treatment for heating the preform as the container preform to a molding temperature at which the preform is molded into a PET bottle as the container; Including, The laser irradiation treatment and the UV light irradiation treatment are performed on the preform after the heat treatment, A container sterilization method characterized in that the cumulative light dose (mJ / cm2) of the CO2 laser applied to the mouth of the preform is greater than the cumulative light dose (mJ / cm2) of the CO2 laser applied to the body of the preform, and / or the cumulative light dose (mJ / cm2) of the UV light applied to the mouth of the preform is greater than the cumulative light dose (mJ / cm2) of the UV light applied to the body of the preform.

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

3. 2. The container sterilization method according to claim 1, wherein the UV light irradiation treatment is performed by irradiating with a UV laser.

4. The laser irradiation process and the UV light irradiation process are carried out by CO ２ 4. The container sterilization method according to claim 3, wherein the method is carried out by irradiating a mixture of laser and UV laser from the same irradiation unit.

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

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

7. A container sterilization device for sterilizing a container surface of a container or a container preform, comprising: CO ２ laser irradiation means for irradiating a laser; UV light irradiation means for irradiating the surface of the container with UV light; a heating means for heating the preform serving as the container preform to a molding temperature at which the preform is molded into a PET bottle serving as the container; Including, the laser irradiation treatment by the laser irradiation means and the UV light irradiation treatment by the UV light irradiation means are performed on the preform after the heating treatment by the heating means, A container sterilization device characterized in that the cumulative light amount (mJ / cm2) of the CO2 laser applied to the mouth of the preform by the laser irradiation means is greater than the cumulative light amount (mJ / cm2) of the CO2 laser applied to the body of the preform, and / or the cumulative light amount (mJ / cm2) of UV light applied to the mouth of the preform by the UV light irradiation means is greater than the cumulative light amount (mJ / cm2) of UV light applied to the body of the preform.

8. A container sterilization method for sterilizing a container surface of a container or a container preform, comprising: a laser irradiation process of irradiating the surface of the container with a laser having an infrared wavelength; a UV light irradiation treatment for irradiating the surface of the container with UV light; a heat treatment for heating the preform as the container preform to a molding temperature at which the preform is molded into a PET bottle as the container; Including, The laser irradiation treatment and the UV light irradiation treatment are performed on the preform after the heat treatment, A container sterilization method characterized in that the integrated light amount (mJ / cm 2 ) of the infrared wavelength laser applied to the mouth portion of the preform is greater than the integrated light amount (mJ / cm 2 ) of the infrared wavelength laser applied to the body portion of the preform, and / or the integrated light amount (mJ / cm 2 ) of the UV light applied to the mouth portion of the preform is greater than the integrated light amount (mJ / cm 2 ) of the UV light applied to the body portion of the preform.

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 surface of the container with a laser having an infrared wavelength; UV light irradiation means for irradiating the surface of the container with UV light; a heating means for heating the preform serving as the container preform to a molding temperature at which the preform is molded into a PET bottle serving as the container; Including, the laser irradiation treatment by the laser irradiation means and the UV light irradiation treatment by the UV light irradiation means are performed on the preform after the heating treatment by the heating means, A container sterilization device characterized in that the integrated light amount (mJ / cm2) of the infrared wavelength laser irradiated by the laser irradiation means onto the mouth portion of the preform is greater than the integrated light amount (mJ / cm2) of the infrared wavelength laser irradiated onto the body portion of the preform, and / or the integrated light amount (mJ / cm2) of UV light irradiated by the UV light irradiation means onto the mouth portion of the preform is greater than the integrated light amount (mJ / cm2) of UV light irradiated onto the body portion of the preform.

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