JPS649219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aseptic filling and packaging method and an apparatus thereof, and its purpose is to irradiate aseptically with electron beams with little risk of secondary radiation contamination.
In addition to sterilizing the packaging material, this irradiation also serves to maintain the sterile state of the sterile room.

Conventionally, methods for sterilizing packaging materials include chemical methods and physical methods. Among these, chemical sterilization methods include hydrogen peroxide sterilization, ethylene oxide gas sterilization, propylene oxide gas sterilization, etc. Among these, ethylene oxide gas sterilization and propylene oxide gas sterilization are effective methods, especially for packaging materials. Although these gases can be sterilized at the final stage of production, they are toxic and their residue in packaging materials becomes a problem.Hydrogen peroxide, which used to be considered relatively safe, has recently become more and more sterile in food. has become an issue and has been debated.

There are various other chemical disinfectants, but at present, none of them are suitable for food-related disinfection because they are either harmful or have low efficacy.

In contrast, physical sterilization, which does not have the problem of drug persistence, is attracting attention. For example, γ rays, ultraviolet rays, etc.

In particular, gamma ray sterilization is a useful sterilization method because it can penetrate plastic packaging materials, so it can be sterilized in the final process like gas sterilization. In fact, it cannot be said that it is suitable for sterilizing food packaging materials.

In addition, for ultraviolet sterilization, ultraviolet rays themselves are less dangerous to the human body than other radiations and are easy to handle;
Only the surface of the packaging material can be sterilized; for example, if dust or the like is attached to the surface of the packaging material, there is a drawback that that part will not be sterilized, and complete sterilization cannot be expected.

In addition to the above-mentioned physical sterilization methods such as gamma rays and ultraviolet rays, there is also an electron beam sterilization method that uses accelerated electron beams.

Unlike gamma rays and ultraviolet rays, the energy of electron beams can be easily changed by accelerating the electron flow extracted from the cathode with high voltage, and the number of emitted electrons (electron current) can also be controlled. As the energy increases, the depth of penetration into the packaging material also increases, making it possible to sterilize objects of any shape.

However, as a basic characteristic of high-energy charged particle beams, when they interact with matter, they increase both ionization loss and radiation loss due to bremsstrahlung radiation of the particles themselves. This becomes especially noticeable when the particle's rest mass is exceeded, and the synchrotron radiation spectrum ranges from x-rays to gamma-rays, and this secondary radiation is not desirable, as mentioned above regarding gamma-rays. .

In view of this, the present invention utilizes an electron beam in the low energy range, which has slightly inferior penetrating power but is less likely to cause secondary radiation contamination. Since the efficiency is better on the low energy side than on the side, it can be said that electron beams in this low energy range are effective and suitable for sterilizing food packaging.

Hereinafter, an apparatus for carrying out the sterilization method of the present invention will be explained with reference to the drawings.

The present invention basically uses an electron beam in the low energy range (500 KeV or less) to sterilize the body material and lid material of the plastic packaging material separately, and also to sterilize the plastic packaging material and the lid material by irradiation with the electron beam. This also serves to maintain the sterile state of the filling and packaging room.

Figure 1 shows the outline of the device.
consists of a preheating section B, a molding section C, a filling section D, and a sealing section E.
And on the side where the lid material b enters, the joint part F ₁
and _F2 , and electron beam irradiation devices _G1 and _G2 are installed.

The plastic packaging material a is placed into the sterile room A from the electron beam irradiation device _G1 side on the right side, and the lid material b of the plastic packaging material containing metal worms is placed into the sterile room A from the left side of the electron beam irradiation device _G2 . The supplied, filled and sealed packages are sent to the electron beam irradiation section.
The product is discharged as a product C through a cutting section H that continues to the sterile room A on the _G2 side.

To explain this device with reference to FIG. 2, a preheating section B in a sterile room A is used to store raw material a sent from outside.
From the preheating plates 1 and 1' on the upper and lower sides of the molding section C
consists of an upper die 2 and a lower die 3 for the filler material a, a filling part D includes a filling nozzle 4 for injecting the contents above the filler material a, and a sealing part E , a shaped body container a′,
heating pressing members 5, 5' for heating and sealing along both side edges above and below the joint with lid material b;
It consists of heating pressing members 6, 6' for heating and sealing the periphery of the molded container a'.

The lid material b, which is sent into the sterile room A from the direction opposite to the direction of the body material a, advances with the inside of the lid facing upward, and after passing the sealing part E, it is reversed by the roll 7 and formed. is connected to container a′,
It is designed to return in the direction it was sent.

Electron beam irradiation devices G ₁ and G ₂ are installed at joint parts F ₁ and F ₂ on the right and left sides of the sterile room A, respectively, on the side from which body material a and lid material b are sent. Electron beam irradiation equipment G ₁ and G ₂
is connected to high voltage transformer _G3 . The electron beam irradiation devices G ₁ and G ₂ have electron opening irradiation windows 8 ₁ and 8 ₂ having titanium foils.

For the sterile room A, an inert gas such as _N2 ,
CO ₂ and other substances are being pumped into the area. That is, the pipes are branched from the inert gas tank T through the prefilter J into pipes 9, 10, 11, and 12, and the pipes 9 and 12 are connected to the electron beam irradiation section _G1 and
The pipes 10 and 11 are connected to the spray nozzles 13 ₁ and 13 ₂ facing the irradiation windows 8 ₁ and 8 ₂ of G ₂ , and the pipes 10 and 11 are connected directly to the sterile room A. Exhaust pipes 14 ₁ and 14 ₂ connected to a blower are provided outside the electron beam irradiation sections G ₁ and G ₂ of the sterile room A.

Next, a filling and packaging method using the apparatus of the present invention will be explained.

The filling section D in the sterile room A is sterilized with steam or the like in advance, and the device is irradiated with an electron beam on the side where the operating contents material a and the lid material b enter.
are sterilely shielded.

For low-density irradiated objects such as plastic packaging,
Since even the back side is sterilized by the penetrating power of the electron beam, the meat material a is sterilized on both the front and back sides before being sent, and in the preheating section B, it is preheated on the preheating plates 1 and 1'.
In the next molding section C, the container a' is molded by an upper mold 2 and a lower mold 3. Container a′ is the next filling part D
At this point, the contents are filled from the filling nozzle 4.

On the other hand, the lid material b containing the metal foil is sent with the inner surface that will become the lid facing upward, is sterilized by the electron beam irradiation device _G2 , is turned over by the roll 7, and is transferred to the container a filled with the contents. ′ is joined with the body material a and proceeds.

The joined body material a and lid material b are sealed along both side edges by the heating pressing members 5 and 5' of the sealing part E, and then the heating pressing members 6 and 6' are used to seal the container.
sealed along the perimeter of a′. The body material a and the lid material b of the container a' sealed in this way are sterilized by passing under the electron beam irradiation device _G2 again, and at the cutting section H in the final stage, each container a' unit or row It is cut into units and discharged as the final product c.

A series of preheating, molding, filling, and sealing processes in the sterile room A are carried out in the inert gas tank T.
This is carried out under positive pressure of an inert gas such as N ₂ or CO ₂ which is introduced into pipes 10 and 11 via prefilter J, and pipes 9 and 12.
_The inert gas injected from the injection nozzles _{13 1} and _{13 2} through _the In addition to avoiding deterioration of the beam irradiation function, harmful ozone generated by the electron beam is replaced with gas and discharged to the outside from the exhaust pipes 14 ₁ and 14 ₂ .

As described above, in the present invention, the product is sent from opposite sides into a sterile room where a series of preheating, molding, filling, and sealing steps are performed by irradiation with electron beams with little risk of secondary radiation contamination. In addition to sterilizing the packaging material and lid material separately, by irradiating the packaging material and lid material on the entrance side, it is possible to maintain the sterile state in the sterile room. In addition to solving the problem of residual disinfectant in conventional chemical sterilization, it also solves the problems of physical sterilization, such as handling of the γ-ray source, radiation control, and the weak penetrating power of ultraviolet rays. It is possible to rationally sterilize each packaging material separately and perform a series of steps such as preheating, forming, filling, and sealing under sterile conditions, making it effective for filling and packaging foods.

In addition, by introducing an inert gas, we can measure the positive pressure inside the sterile room, prevent the invasion of bacteria from the outside, and avoid the deterioration of the electron beam irradiation function. By replacing the ozone with gas and discharging it to the outside, the safety of the equipment and its functionality can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the apparatus of the present invention, and FIG. 1 is a schematic diagram thereof, and FIG. 2 is a sectional view showing only the necessary configuration. Code A...sterile room, B...preheating section, C...molding section, E...sealing section, _F1 , _F2 ...joint section,
_G1 , _G2 ...Electron beam irradiation section, H...Cutting section, T...Inert gas tank, J...Prefilter, a...Body material, b...Lid material, c...Product.

Claims (1)

[Claims] 1. Using an electron beam with low risk of secondary radiation contamination, the body and lid of plastic packaging materials that are fed into a sterile room from opposite sides are separated at the entrance thereof. In addition to sterilization, the electron beam irradiation at this entrance allows preheating, shaping, and
An aseptic filling and packaging method that also maintains the conditions inside a sterile chamber in which a series of steps of filling and sealing contents is performed. 2. Claim 1 provides that the series of steps in a sterile room are performed under positive pressure of inert gas.
Aseptic filling and packaging method described in Section 1. 3 The electron beam irradiation equipment, which has a low risk of secondary radiation contamination of the body material and lid material of plastic packaging materials fed from opposite sides, is used to preheat and mold the body material, and to It forms a sterile chamber in which a series of processes of filling the body material with the contents and sealing with the lid material is performed, and this sterile chamber is maintained in a sterile state by the above-mentioned electron beam irradiation device. Aseptic filling and packaging equipment. 4 The relationship between the above-mentioned lid material and the electron irradiation device is that before the lid material is sealed to the body material, it is on the inner surface of the lid, and after sealing, it is positioned so that it irradiates the surface side. An aseptic filling and packaging apparatus according to claim 3. 5 The electron beam irradiation equipment, which has a low risk of secondary radiation contamination of the body material and lid material of plastic packaging materials fed from opposite sides, is used to preheat and mold the body material, and to It forms a sterile room where a series of processes are carried out, including filling the body material with the contents and sealing with the lid material.
This sterile room is kept in a sterile state using the above-mentioned electron beam irradiation device, and is also equipped with means for introducing inert gas to maintain a positive pressure inside the room, and an electron beam irradiation device. An aseptic filling and packaging device is provided with an evacuation means for replacing and discharging harmful ozone generated in the process, and a means for blowing an inert gas onto an irradiation window of an electron beam irradiation device.