JP4713649B2 - Preform sterilization method - Google Patents

Description

  When aseptically filling fruit juice beverages, coffee beverages, other soft drinks, etc. into polyethylene terephthalate bottles (hereinafter referred to as PET bottles) or paper containers, PET bottles, PET bottle preforms, paper containers, etc. The present invention relates to a sterilization method for sterilizing a container.

Conventionally, when aseptically filling fruit juice drinks, coffee drinks, etc., packaging materials such as containers or lids used therein must be sterilized in advance before filling the contents.
Therefore, conventionally, the following method is used as a method for sterilizing a molded container such as a plastic container such as a PET bottle.
There is a method in which a molded PET bottle is supplied to an aseptic filling machine, and an aqueous solution of hydrogen peroxide as a sterilizing agent is sprayed into the container in the aseptic filling machine, and then dried to sterilize the container and aseptically fill the contents.
In addition, a small amount of bactericidal agent is dropped on the inner surface of the bottle when molding a PET bottle, and the inside of the bottle is sterilized with vaporized bactericidal agent (hydrogen peroxide) sealed by the mouth, and this sterilized bottle is aseptically filled. And sterilizing the outer surface of the bottle in an aseptic filling machine, then opening the mouth and aseptically filling the contents (for example, Patent Document 1, Patent Document 2, Patent Document 3, (See Patent Document 4).

A PET bottle is manufactured by producing a preform by injection molding and stretching and blowing the preform with a blow molding machine. However, since the preform is injection molded at 260 to 280 ° C., it is in a heat-sterilized state. is there.
Using the heat-sterilized preform, PET injection bottle molding, bottle blow molding, and aseptic filling of contents are integrated and these devices are enclosed in a sterile chamber, so that PET bottles are not sterilized. A method is also disclosed (for example, see Patent Document 5).
A method is also disclosed in which a preform is sterilized and washed, and then blow-molded in an aseptic environment to produce an aseptic PET bottle, and this PET bottle is aseptically filled (see, for example, Patent Document 6).
Also, the aqueous hydrogen peroxide solution is heated to a boiling point or higher and vaporized, and the gaseous hydrogen peroxide is sprayed into the air to condense the hydrogen peroxide into fine mist and adhere to the container. The method of sterilizing the container by using the method is used.

JP-A 63-281937 Japanese Laid-Open Patent Publication No. 1-167031 JP-A-1-254523 JP-A-8-244729 JP-A-8-164925 JP-A-8-282789

However, in the method according to Patent Document 1, the PET bottle in the final form is sterilized in an aseptic filling machine, and thus the PET bottle has the highest reliability in terms of sterility. Need to be transported.
Therefore, there are problems related to logistics such as transportation costs and warehouse space, and reduction of product costs has become a major issue.
In addition, when transporting PET bottles, contamination by microorganisms, especially microbial contamination on the top of the mouth of the PET bottle, is unavoidable. It was necessary to tighten the conditions.
Next, in the case of Patent Documents 2 to 4, immediately after molding the PET bottle, the bottle is still in a clean state by dropping a bactericidal agent and sealing it, and sterilizing the inner surface of the bottle. However, logistics such as transportation costs and warehouse spaces have the same problems as the method according to Patent Document 1 described above.

  Developed as a logistics measure above, PET bottles were not supplied, but container manufacturers supplied bottle precursors called preforms before blow molding, and beverage manufacturers (users) bottled in the factory. Is a method according to Patent Document 5 and Patent Document 6 described above, in which the bottle is supplied in-line to an aseptic filling machine and the contents are aseptically filled.

  However, the method according to Patent Document 5 integrates the injection molding from molding the preform to the aseptic filling of the contents in the aseptic chamber, so that the injection molding machine and preform for molding the preform are integrated. The blow molding machine that performs blow molding and the aseptic filling machine that fills and seals the contents must all operate smoothly. Once a trouble occurs in any of the machines, the entire system stops, so the overall system availability It was very difficult in terms of operation because it required a lot of time and labor to sterilize the entire system at the time of re-operation.

In addition, in the case of Patent Document 6, since the preform is sterilized with a sterilizer and then blown aseptically with a blow molding machine and aseptically filled into the sterile bottle, a sterilizer for preforms is employed. And the blow molding machine needs to be aseptic.
For this reason, the entire apparatus is increased in size to increase the equipment cost, and it is very difficult to stably maintain sterility.

  The present invention reduces the number of bacteria attached to a preform as much as possible in an in-line aseptic filling method of a PET bottle in which a preform is supplied, a bottle is blow-molded, the inside and outside surfaces of the bottle are sterilized and the contents are aseptically filled. In order to reduce the sterilization load of molded bottles and increase the sterilization efficiency, thereby reducing the defective rate of aseptic filling products, we provide a method to pre-sterilize preforms before delivery To do.

In other words, the preform is sterilized before delivery to the food manufacturer (user), and the sterilized preform is supplied to extremely reduce the degree of microbial contamination of the molded bottle and increase the sterilization efficiency of the PET bottle. is there.
In addition, when pre-sterilizing the preform, by using hydrogen peroxide diluted with a volatile solvent such as ethyl alcohol as a bactericidal agent, the hydrogen peroxide solution spreads quickly on the inner surface of the preform, and the inner surface A thin film is formed, which accelerates the evaporation rate of hydrogen peroxide, shortens the sterilization time compared with the conventional aqueous hydrogen peroxide solution, and eliminates the need to completely seal the preform. The process was simplified and the work efficiency was improved.

In order to solve the above problem, the container sterilization method was as follows.
That is, in a container sterilization method in which an aqueous hydrogen peroxide solution is dropped on the inner surface of a plastic molded container, a paper container or the like, and the aqueous hydrogen peroxide solution is vaporized to sterilize the inner surface of the container. A container sterilization method is characterized in that a volatile solvent such as alcohol, methyl alcohol, acetone, isopropyl alcohol, or a hydrogen peroxide solution prepared by diluting with a mixed solvent thereof is dropped onto the inner surface of the container.
The container to be sterilized is a bottle for producing a preform by an injection molding method, forming the preform into a blow bottle with a blow molding machine, and aseptically filling and sealing the sterilized contents in the blow bottle. A container sterilization method characterized by being a preform used in an aseptic filling system.

And, on the inner surface of the preform manufactured by the injection molding method, a hydrogen peroxide solution diluted with the volatile solvent is dropped, the preform is stored in a container, the container is being transported or stored, A container sterilization method is characterized in that the hydrogen peroxide solution dropped on the inner surface of the preform is vaporized and the inner surface of the preform is sterilized with the vaporized hydrogen peroxide vapor.
Furthermore, the hydrogen peroxide concentration used for the sterilization is 0.1 to 10% by weight, and the amount of hydrogen peroxide dropped on the inner surface of the container is 0.05 to 100 μl. The container was sterilized.

  That is, in the present invention, as a method of sterilizing the inner surface of a plastic molded container, paper container or the like, a hydrogen peroxide aqueous solution as a sterilizing agent is a volatile solvent such as ethyl alcohol, methyl alcohol, acetone, isopropyl alcohol, Alternatively, using a solution diluted with these mixed solvents, the diluted solution of hydrogen peroxide is dropped on the inner surface of the container, and the container is packaged with an outer packaging material such as a plastic bag, cardboard, or container, and evaporated. It was set as the method of maintaining the sealed form so that hydrogen oxide does not volatilize, the hydrogen peroxide dripped on the inner surface of the container being vaporized together with the diluting solvent, and sterilizing the inner surface of the container with the hydrogen peroxide vapor.

By diluting the hydrogen peroxide solution with a volatile solvent, the hydrogen peroxide solution spreads quickly on the inner surface of the preform, and a thin film is formed on the inner surface. This accelerates the evaporation rate of hydrogen peroxide. Compared with hydrogen peroxide aqueous solution, the sterilization time on the inner surface of the container could be shortened.
In addition, when the inner surface of a paper container such as a paper cup is sterilized using an aqueous hydrogen peroxide solution, hydrogen peroxide vapor is less likely to penetrate into the gap between the body part of the paper container and the heat seal part or the body pasting part of the bottom part. The complete sterilization of the part was very difficult, but when hydrogen peroxide was diluted with a volatile solvent, the penetration of the hydrogen peroxide solution was very good, and the heat seal part at the bottom and bottom of the paper container And sterilization of the body sticking part has become easy.

In addition, the sterilization method of the present invention is used for a preform used in a blow bottle for aseptic filling as a container to be sterilized.
That is, a PET bottle preform used for aseptic filling is put in a container or the like and transported to a user such as a food manufacturer, and the user forms the preform into a bottle with a blow molding machine, and the bottle is made into a sterile filling machine. Supply and sterilize the inner and outer surfaces of the bottle in an aseptic chamber, and aseptically fill the sterilized bottle with the sterilized contents, add hydrogen peroxide diluted with a volatile solvent dropwise to the preform and put it in the container. The hydrogen peroxide dropped on the preform during transportation or storage at the user is vaporized together with a volatile solvent, and the hydrogen peroxide vapor sterilizes the inner surface of the container. Yes.

  As described above, by pre-sterilizing the preform, the bottle molded by the blow molding machine has a very low degree of contamination by microorganisms, and then the inner surface sterilization and the outer surface sterilization of the bottle by the aseptic filling machine. In the process, the sterilization efficiency is improved and, in some cases, the sterilization conditions can be loosened, so that work efficiency such as shortening of the sterilization process time can be improved.

In addition, when a paper container is supplied to an aseptic filling machine and sprayed with an aqueous hydrogen peroxide solution on its inner surface to sterilize, the heat seal part and the cylinder pasting part of the body part and the bottom part have hydrogen peroxide vapor in the gap between them. It was difficult to penetrate, so it was necessary to increase the sterilization conditions such as increasing the temperature of the aqueous hydrogen peroxide solution or extending the sterilization time. However, if the paper container is pre-sterilized by the sterilization method of the present invention, Since the heat seal part and the body pasting part at the bottom and bottom are already sterilized, the paper container is completely sterilized even if the sterilization conditions in the aseptic filling machine are loosened.
Therefore, since the paper container can be sterilized even if the sterilization time is shortened, the production capacity of the aseptic filling machine is improved, and the product cost can be reduced.

According to the present invention, when a PET bottle preform used for aseptic filling is placed in a container or the like and transported to a food manufacturer (user), a hydrogen peroxide solution diluted with a volatile solvent is added to the preform. The preform is preliminarily sterilized by dropping and during transportation or storage by a user.
As described above, by pre-sterilizing the preform, the bottle molded by the blow molding machine has a very low degree of contamination by microorganisms, and then the inner surface sterilization and the outer surface sterilization of the bottle by the aseptic filling machine. In the process, the sterilization efficiency is improved and, in some cases, the sterilization conditions can be loosened, so that work efficiency such as shortening of the sterilization process time can be improved.

In addition, when a paper container such as a paper cup is supplied to an aseptic filling machine and sprayed with an aqueous hydrogen peroxide solution on its inner surface to sterilize, the heat seal part and the cylinder pasting part on the body and bottom are overoxidized in the gap between the parts. Since hydrogen vapor hardly penetrates, it was necessary to increase the sterilization conditions such as increasing the temperature of the aqueous hydrogen peroxide solution or extending the sterilization time. However, the paper container should be pre-sterilized with the sterilization method of the present invention. For example, since the gap between the heat seal part and the cylinder pasting part of the body part and the bottom part has already been sterilized, the paper container is completely sterilized even if the sterilization conditions in the aseptic filling machine are loosened.
Therefore, since the paper container can be sterilized even if the sterilization time is shortened, the production capacity of the aseptic filling machine is improved, and the product cost can be reduced.

Also, depending on the contents, as in acidic foods such as fruit juice and mineral water, the preform is sterilized in advance, so that only the mouth of the blow-molded bottle is sterilized, and it is aseptic without sterilizing the inner surface of the bottle. Since filling becomes possible, the inner surface sterilization step of the bottle in the aseptic filling machine can be omitted, so that the aseptic filling machine can be miniaturized and the production capacity of the aseptic filling machine can be greatly improved.
Furthermore, since no germicide such as hydrogen peroxide is used in the aseptic filling machine, the working environment is greatly improved, and hydrogen peroxide exhaust facilities and exhaust hydrogen peroxide treatment facilities are not required. The equipment cost can be reduced.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a container sterilization method of the present invention.
FIG. 2 is a view showing a representative example of a container other than the preform to be subjected to the sterilization method of the present invention.
FIG. 3 is an explanatory diagram when the sterilization method of the present invention is used for a preform.
FIG. 4 is a diagram showing a process when a sterilization method of the present invention is used for a preform, a bottle is formed from the preform, and the bottle is aseptically filled.
FIG. 5 is an explanatory view when a bottle is formed using a pre-sterilized preform, and the mouth of the bottle is sterilized by ultraviolet sterilization.
FIG. 6 is a view showing the structure of the heat seal part and the cylinder pasting part of the body part and the bottom part of the paper cup.
FIG. 7 is an explanatory diagram when the sterilization method of the present invention is used in a paper cup.
FIG. 8 is an explanatory diagram when the preform is sterilized according to the first embodiment.
FIG. 9 is an explanatory diagram when the paper cup is sterilized according to the fourth embodiment.

The container sterilization method of the present invention basically has a hydrogen peroxide solution 11 (hereinafter referred to as H ₂ O _{2) obtained} by diluting hydrogen peroxide with a volatile solvent such as ethyl alcohol as shown in FIG. 1) is dropped on the inner surface of a container 20 such as a plastic container or a paper container, and the container 20 in which the H ₂ O ₂ solution 11 is dropped is placed in a container 3 ( or cardboard, by sealing with the cover 4 placed in a plastic bag, etc.), evaporated H ₂ O ₂ solution 11 was dropped on the inner surface of the container 20 in the container 3, the vaporized H ₂ O with volatile solvents _{2 This} is a method of sterilizing the inner surface of the container with steam 11a.

That is, when a container for aseptic filling is manufactured and carried into a user, the container 20 into which the H ₂ O ₂ solution 11 diluted with a volatile solvent is dropped is placed in the container 3 and sealed, and this container is sealed with a food manufacturer ( While the container is being transported to the user and the container is being stored, the H ₂ O ₂ solution 11 dripped into the container 20 in the container 3 is vaporized, and the vaporized H ₂ O ₂ vapor 11a causes the H ₂ O ₂ vapor 11a to It is intended to sterilize the inner surface.
Further, the H ₂ O ₂ vapor 11a vaporized in the container 3 goes out of the container 20 together with the volatile solvent with time, and fills the container, so that the outside of the container 20 is also sterilized. become.

As the hydrogen peroxide used in the present invention, a commercially available hydrogen peroxide solution having a hydrogen peroxide concentration of 30 to 35% by weight is usually used.
A 3% by weight aqueous hydrogen peroxide solution marketed as oxidol can also be used. As a 30 to 35% hydrogen peroxide aqueous solution (hereinafter, the weight% of hydrogen peroxide concentration is simply described as%), there are industrial use and food additive use, and both can be used in the present invention. For industrial use, a stabilizer or the like is added to prevent decomposition of hydrogen peroxide, and therefore a hydrogen peroxide aqueous solution for food additives with few additives is suitable.
In the present invention, a 30 to 35% aqueous hydrogen peroxide solution for food additives is used, diluted with the following volatile solvent, and used as a 0.1 to 10% solution.
The concentration of H ₂ O ₂ solution and the amount of dripping differ depending on the size of the container to be sterilized, but usually 0.5 to 5% solution is used, and the amount of dripping is 0.05 to 5 as H ₂ O ₂ solution. It is used in the range of 100 μl, preferably about 1 to 30 μl.

As the volatile solvent used in the present invention, hydrogen peroxide or an aqueous hydrogen peroxide solution can be used as long as it is soluble and volatile, but ethyl alcohol, methyl alcohol, isopropyl alcohol, Acetone is preferred.
In particular, ethyl alcohol is more preferable in terms of handling such as compatibility with an aqueous hydrogen peroxide solution, wettability to plastic materials, permeability, and evaporation rate.
By using a volatile solvent as the diluting solvent for the aqueous hydrogen peroxide solution, the hydrogen peroxide solution dripped onto the container forms a thin film on the inner surface of the container and spreads wet, and the evaporation rate is accelerated. The vapor pressure is increased, the sterilization efficiency is improved, and the sterilization time of the container can be shortened.

That is, since the boiling point of hydrogen peroxide is 151.4 ° C., when the container in which the aqueous hydrogen peroxide solution is dropped is stored at a room temperature of 15 ° C. or less, the evaporation rate of the aqueous hydrogen peroxide solution is slowed down, which makes it considerably effective for sterilization. And a sufficient hydrogen peroxide vapor pressure necessary for sterilization cannot be obtained, and sterilization of the inner surface of the container may be insufficient.
Therefore, in the present invention, a 35% hydrogen peroxide aqueous solution is diluted with a volatile solvent such as ethyl alcohol, and this diluted solvent is dropped on the inner surface of the container, whereby a thin film of the hydrogen peroxide solution is formed on the inner surface of the over container. In addition, the evaporation rate of hydrogen peroxide in the container is promoted to increase the H ₂ O ₂ vapor pressure, the container is sterilized more efficiently, and the sterilization time is shortened. .

The container sterilization method of the present invention can be used for plastic molded containers, paper cups, paper containers and the like in addition to the preforms described above.
For example, as shown in FIGS. 2A to 2F, a plastic molding container 21 molded from a plastic sheet, a plastic molding container 21a produced by an injection molding method, a paper cup 22, a cylindrical paper container 23, a taper The rectangular paper container 23a and the like are to be sterilized.
Furthermore, it can be used for plastic bottles such as PET bottles.

Next, a method of using the container sterilization method of the present invention as a preform, forming the sterilized preform into a bottle with a blow molding machine, and subjecting the bottle to aseptic filling will be described. First, the preform 1 is produced using an injection molding machine as shown in FIG.
In the case of a PET bottle, the preform 1 is molded using a polyethylene terephthalate resin (hereinafter referred to as “PET resin”). However, the preform 1 is not limited to the PET resin and may be manufactured using nylon or other thermoplastic resin.

Next, as shown in FIG. 3B, a solution obtained by diluting a 35% aqueous hydrogen peroxide solution with a volatile solvent such as ethyl alcohol, that is, an H ₂ O ₂ solution 11 is formed in the preform 1. The preform 1 to which the H ₂ O ₂ solution 11 is dropped is placed in a container 3 and sealed with a lid 4 as shown in FIG.
The container 3 containing the preform 1 is transported to the user (food manufacturer, etc.). The H ₂ O ₂ solution diluted with a volatile solvent has a hydrogen peroxide (H ₂ O ₂ ) concentration of 0.1 to 10%. When diluted with ethyl alcohol, H ₂ O _{2 is used.} The concentration is preferably about 0.5 to 5%.
Further, the H ₂ O ₂ solution dropped on the preform 1 varies depending on the dilution solvent, and is dropped in the range of 0.1 to 100 μl, but preferably 1 to 30 μl when diluted with ethyl alcohol.

As shown in FIG. 3 (c), the preform 1 to which the H ₂ O ₂ solution has been dropped is placed in a container 3 and sealed, temporarily stored, transported to the user, and stored again by the user. After that, it is formed into a bottle by a blow molding machine.
The H ₂ O ₂ solution dropped on the preform 1 is vaporized in a container during storage or transportation, and the vaporized H ₂ O ₂ vapor 11a sterilizes the inner surface of the preform.
That is, the H ₂ O ₂ solution 11 dropped on the preform 1 is a volatile solvent, so that it quickly evaporates after being dropped on the preform 1 and fills the inside of the preform 1. .
At the same time, H ₂ O ₂ evaporates together with the diluting solvent, becomes H ₂ O ₂ vapor 11a, contacts the inner surface of the preform 1, and sterilizes the inner surface of the preform 1.
For diluent in H ₂ O ₂ is volatile solvent, is accelerated evaporation rate of the H ₂ O ₂ is a short time it becomes H ₂ O ₂ vapor 11a, the H ₂ O ₂ vapor 11a of the preform Since the density is increased, the sterilizing effect on the inner surface of the preform 1 is increased.

In addition, since the opening of the preform 1 stored in the container 3 remains in an open state, the H ₂ O ₂ vapor 11a that has evaporated in the preform 1 is left outside the preform 1 over time. Although it goes out, since the container 3 is covered with the lid 4 and is in a sealed state, the H ₂ O ₂ vapor 11a is trapped in the container and the outside of the preform is also sterilized.
When injection molding a preform using PET resin, the molding temperature is 260 to 280 ° C., so the preform is completely aseptic when molding, so even if it is contaminated with microorganisms in the subsequent operation, Since the outside of the preform is quite clean and has little microbial contamination, it is sterilized by the H ₂ O ₂ vapor 11a, leaving almost no viable count.
However, since the density of the H ₂ O ₂ vapor 11a in the container 3 is considerably lower than that inside the preform 1, complete sterilization cannot be expected when there is a large amount of microbial contamination outside the preform 1.

Next, the preform 1 sterilized on the inner surface and the outer surface is put in a container, carried into a user, supplied to a blow molding machine, and molded into a blow bottle.
That is, as shown in FIG. 4A, the sterilized preform 1 is blow-molded by a blow molding machine (not shown) to form a bottle 2 as shown in FIG. 4B.
Next, the bottle 2 is supplied to an aseptic filling machine, and as shown in FIG. 4 (c), the H ₂ O ₂ mist 11b is adhered to the inner surface of the bottle by spraying an aqueous hydrogen peroxide solution in an aseptic chamber. The inner surface of the bottle is sterilized by drying with hot air. Further, as shown in FIG. 4 (d), the H ₂ O ₂ mist 11b is attached to the outer surface of the bottle and dried as shown in FIG. Sterilize.

In the above process, when a bottle is molded by a blow molding machine using the sterilized preform 1, it can be operated in a clean state using a normal blow molding machine without using an expensive aseptic blow molding machine. For example, since the molded bottle has very little microbial contamination, the load of sterilization can be reduced in the next sterilization step, and the sterilization efficiency can be improved.
That is, since the microbial contamination of the bottle is very small, the amount of H ₂ O ₂ mist adhering to the bottle can be reduced in the bottle sterilization process.
Therefore, as the drying time is shortened, the sterilization process time is also shortened, so that the sterilization capacity of the aseptic filling machine is increased and the production capacity is improved.
Further, when the microbial contamination of the bottle is extremely reduced, the bottle sterilization defect is eliminated and the bottle sterilization effect is enhanced, so that the defective rate of the aseptic filling product is reduced and the production efficiency of the aseptic filling machine is improved.

As shown in FIG. 4E, the sterilized bottle 2 is inverted in a sterile chamber, and the inside of the bottle is washed by spraying sterile water 13 from the washing water nozzle 12 into the bottle.
By this washing step, dust adhering to the inside of the bottle and H ₂ O ₂ remaining slightly are washed away to clean the inside of the bottle.
Next, the cleaned bottle is moved to the filling process with the mouth side up, and the bottle is placed under the filling nozzle 14 and filled with the sterilized contents 15 as shown in FIG. 4 (f). Then, the process moves to the capping process, and as shown in FIG. 4 (g), the cap 5 sterilized in another process is put on and the aseptic filling product 6 is produced.

In addition, when performing aseptic filling of bottles using the preform sterilized by the sterilization method of the present invention, depending on the contents, aseptic filling can be performed without sterilizing the inner and outer surfaces of the bottle, the aseptic filling machine can be reduced in size. And the production capacity can be improved, so that the cost of the product can be reduced.
That is, in the case of acidic foods such as orange juice or mineral water, as shown in FIG. 5 (a), after preform 1 is injection molded, sterilized preform 1 in the same manner as described above is bottled with a blow molding machine. The bottle 2 is produced as shown in FIG.

Next, the bottle 2 is supplied to an aseptic filling machine, and in the aseptic chamber, as shown in FIG. 5 (c), ultraviolet rays (sterilization lines) are emitted from an ultraviolet irradiation device 17 equipped with a germicidal lamp at the mouth of the bottle. To sterilize the mouth of the bottle.
As a germicidal lamp, a low-pressure mercury lamp that emits a germicidal line having a wavelength of 253.7 nm is generally used. However, a high-pressure mercury lamp may be used as a high-powered germicidal lamp.
In the process of forming the sterilized preform 1 into a bottle with a blow molding machine and supplying it to the aseptic filling machine, the bottle mouth has a high possibility of microbial contamination from the outside and directly touches the contents. By sterilizing the mouth, the defective rate of aseptically filled products can be reduced.
The bottle 2 with the sterilized mouth is washed with sterile water in an inverted state as shown in FIG. 5 (d), and then filled as shown in FIGS. 5 (e) and (f). The contents 15 are filled in the process, and the cap 5 is put in the capping process to obtain the aseptic filling product 6.

Further, the container sterilization method of the present invention can be used for paper cups and paper containers made of paper.
Below, the sterilization method of the paper cup using the laminated material which consists of paper, a plastic film, and aluminum foil is demonstrated.
6A is a perspective view in which a part of the paper cup is cut out, FIG. 6B is a vertical cross-sectional view of the paper cup, and FIG. 6C is a cross-sectional view of the body pasting portion of the paper cup. .
As shown in FIGS. 6 (a) and 6 (b), a paper cup used for aseptic filling is prepared by using a laminated material in which a heat-sealable film such as polyethylene is laminated on the inner surface and outer surface of the laminated material. Then, the bottom 25 produced using the same laminated material is heat-sealed inside the trunk portion 24 to form a paper cup 22.
Further, as shown in FIG. 6C, the body pasting portion 26 of the body portion of the paper cup 22 bends one end that becomes the inner side of the laminated material to the outside, and the inner end surface of the laminated material contacts the contents. It has a structure that does not.

Since the paper cup 22 has the above-described structure, there is a slight gap between the heat seal portion of the body portion 24 and the bottom portion 25 and the heat seal portion of the body pasting portion 26 (the heat seal portion of the body portion and the body portion). Thus, in the conventional sterilization method, it is difficult to infiltrate the sterilizing agent into the gap between the portions, and sterilization is very difficult.
However, in the present invention, the disinfectant H ₂ O ₂ is diluted with a volatile solvent and dropped into the paper cup 22, so the diluted solvent has high permeability, so the dropped H ₂ O ₂ solution Penetrates into the gap of the heat seal part, H ₂ O ₂ is vaporized together with the volatile solvent, and H ₂ O ₂ vapor is present in the paper cup as a mixed gas together with the vapor of the volatile solvent. , H ₂ O ₂ vapor has improved permeability, and can penetrate into the heat seal portion between the body portion 24 and the bottom portion 25 and the gap between the heat seal portion between the body portion and the body portion to sterilize this portion. it can.

Next, a paper cup sterilization method will be described. First, as shown in FIG. 7A, a paper cup 22 is produced by a known method using a paper cup molding machine.
Next, as shown in FIG. 7B, in the paper cup 22, as in the case of the preform, a solution obtained by diluting a 35% aqueous hydrogen peroxide solution with a volatile solvent such as ethyl alcohol, that is, H _2. O ₂ solution 11 was dropped, the H ₂ O ₂ solution 11 paper cup 22 was dropped, as shown in FIG. 7 (c), and sealed with a lid placed on cardboard or container stacked, the user this To be transported to.

As shown in FIG. 7C, the H ₂ O ₂ solution 11 dropped on the paper cup 22 is vaporized together with a volatile solvent during storage or transportation, and becomes H ₂ O ₂ vapor 11a. Sterilize the inside of the.
Since the diluting solvent of H ₂ O ₂ is a volatile solvent, hydrogen peroxide (H ₂ O ₂ ) evaporates together with the volatile solvent, so that evaporation of H ₂ O ₂ is promoted and H ₂ in the paper cup 22 is accelerated. The density of ₂ O ₂ vapor 11a increases.
Further, since the H ₂ O ₂ vapor 11a is present in the paper cup 22 as a mixed gas together with the volatile solvent vapor, the heat seal between the body portion 24 and the bottom portion 25 together with the permeable solvent vapor having good permeability. It penetrates also into the gap between the parts and the gap between the body part and the heat seal part between the body parts, and this part is quickly sterilized.
Therefore, the sterilization time can be shortened as compared with a conventional paper cup sterilization method using an aqueous hydrogen peroxide solution.

In the case of a conventional paper cup sterilization method using an aqueous hydrogen peroxide solution, sterilization may take several days. However, in the sterilization method of the present invention, sterilization is completed in 1 to 2 days.
Even when the room temperature is as low as 10 to 15 ° C., the vapor density of H ₂ O ₂ is increased and the permeability is improved, so that it can be sufficiently sterilized in 1 to 2 days.
Therefore, the sterilization method of the present invention is a very excellent sterilization method as a paper cup sterilization method.
Even in the case where the cross section of the paper is in contact with the contents in the body pasting portion of the paper cup, if the sterilization method of the present invention is used, the H ₂ O ₂ vapor penetrates and sterilizes the cross section of the paper cup. , Microbial contamination from the cross section of the paper can be prevented.
Hereinafter, the present invention will be described in more detail based on examples.

Using a polyethylene terephthalate resin (manufactured by Teijin Ltd.), a preform 1 (inner diameter 21 mmφ, height 155 mm) for a PET bottle (volume 2 l) is produced as shown in FIG. did.
Next, a suspension of Bacillus subtilus spore resistant to hydrogen peroxide is sprayed on the inner surface of the preform and dried at room temperature, as shown in FIG. 8 (b). 10 @ 3 and 10 @ 4 Bacillus subtilis spores 7 were attached to the inner surface of the reform 1 to prepare 200 of each.

Then diluted 35% hydrogen peroxide aqueous solution at 99.5% ethyl alcohol, H ₂ O ₂ concentration to make a 1% and 2.5% solution as a dilute solution of H ₂ O _2, FIG. As shown in FIG. 8 (c), 20 μl was dropped on the inner surface of the preform 1 to which the Bacillus subtilis spores 7 were adhered, and 1% H ₂ O ₂ solution was applied to the preform 1 to which 10 3 Bacillus subtilis spores 7 were adhered. 100 were added dropwise and 100 were added dropwise with a 2.5% H ₂ O ₂ solution.
Similarly, for even preform 1 spores 7 of Bacillus subtilis was 104 pieces adhere, 100 what was dropped with 1% H ₂ O ₂ solution, a material obtained by dropwise addition of 2.5% H ₂ O ₂ solution 100 I made this book.

As shown in FIG. 8 (d), 100 preforms in which the H ₂ O ₂ solution 11 was dropped as described above were placed in a polyethylene bag (hereinafter referred to as a PE bag). The preform 1 was sterilized by storing it at room temperature (15 to 20 ° C.) for 2 days.
After storage, the preform is opened and taken out, and 10 ml of the 100 preforms are aseptically dispensed with 20 ml of tryptic soy bouillon medium, sealed with a sterilized cap, and cultured at 35 ° C. for 5 days. did.
As a comparative example, tryptosoy bouillon medium was dispensed in the same manner as above to 10 preforms each having 10 ³ and 10 ⁴ adherent spores of Bacillus subtilis and cultured at 35 ° C. for 5 days.
After culturing, the turbid state of the medium in the preform was observed, and those without turbidity were completely sterilized, and those with turbidity were determined to be incompletely sterilized.
0/10 in Table 1 indicates that 0 of the 10 preforms has turbidity, and 10/10 indicates that 10 of 10 preforms have turbidity.

The results are as shown in Table 1. The preforms with 10 ³ and 10 ⁴ Bacillus subtilis spores were completely sterilized by dropping H ₂ O ₂ solution (1% and 2.5%). It had been.
That is, the sterilization method of the present invention can completely sterilize up to 10 ⁴ spores of Bacillus subtilus, and thus the sterilization effect is 4 or more.
In general, since the number of bacteria attached to the preform is several to several tens at most, it can be predicted that the normal preform can be completely sterilized by using the sterilization method of the present invention.

(Table 1)
┌───────┬────────────┬───────┐ │Preform│H ₂ O ₂ concentration used for sterilization│Comparative example │ │付 着 ─────┬──────┼───────┤ │ │ 1% │ 2.5% │ No sterilization │ ├───────┼─── ──┼──────┼───────┤ │ 10 ³ │ 0/10 │ 0/10 │ 10/10 │ ├───────┼─────┼ ──────┼───────┤ │ 10 ⁴ │ 0 / 10│ 0/10 │ 10/10 │ └───────┴─────┴─── ───┴───────┘

In the same manner as in Example 1, a preform for a PET bottle (volume 2 l) was produced.
Similarly to Example 1, a 1% H ₂ O ₂ solution of ethyl alcohol was prepared, and 20 μl of the 1% H ₂ O ₂ solution was dropped onto the 200 preforms. It was packed in cardboard and stored at room temperature for 2 days.
As a comparative example, 200 preforms in which no H ₂ O ₂ solution was dropped were similarly packed in cardboard and stored at room temperature for 2 days.

All the preforms stored at room temperature for 2 days were put in a tryptosoy bouillon medium, capped and cultured at 35 ° C. for 2 hours, as in Example 1.
After culturing for 2 days, the turbid state of the medium was observed in the same manner as in Example 1 to determine whether or not the preform was sterilized.
As a result, the 200 preforms dropped with the H ₂ O ₂ solution did not become turbid, but in the case of the comparative example, turbidity occurred in 3 of the 200 preforms.
That is, in the preform molded by injection molding, microbial contamination was observed in 3 of the 200 preforms, but the contaminated preform was completely sterilized by dropping 1% H ₂ O ₂ solution. We were able to.

In the same manner as in Example 1, a preform for a PET bottle (volume: 2 liters) was prepared, and 20 μl of 1% H ₂ O ₂ ethyl alcohol solution was dropped on 1000 preforms immediately before the preform was placed in a container. Then, as shown in FIG. 3C, the container was transported to a food manufacturer (user) in a container.
A food manufacturer forms the above preform into a 2 liter bottle with a blow molding machine, supplies the bottle to an aseptic filling machine, and sterilizes only the mouth of the bottle by ultraviolet irradiation without sterilizing the inner surface of the bottle. Then, according to a conventional method, 2 l of a sterilized liquid medium (tryptosy bouillon medium) was filled to produce 1000 aseptic filled bottles.
As a comparative example, using a preform to which no H ₂ O ₂ solution was added, it was molded into a bottle with a blow molding machine, filled with a liquid medium sterilized with an aseptic filling machine, and filled with a liquid medium. 1000 medium-filled bottles were produced.

After the medium-filled bottle prepared as described above was cultured at 35 ° C. for 5 days in the same manner as in Example 1, the turbidity of the medium was observed in the same manner as in Example 1 to determine whether the bottle was sterilized. .
As a result, did not produce a bottle all turbidity using a preform was added dropwise H ₂ O ₂ solution, in the case of bottles using a preform not drip the H ₂ O ₂ solution, 30 present in the 1000 Turbidity occurred and microbial contamination was observed.
That is, by dripping a 1% H ₂ O ₂ solution onto a preform to sterilize the preform, a bottle molded using the same sterilizes only the mouth and does not sterilize the inner surface of the bottle. Turned out to be uncontaminated.
In addition, as a result of measuring a hydrogen peroxide concentration in a bottle formed with a preform dropped with a H ₂ O ₂ solution, filling the bottle with distilled water, the detection limit (0.01 ppm) or less Thus, it was found that H ₂ O ₂ dropped on the preform did not remain in the bottle.

Using a laminate composed of PE / paper / PE / Al / PE (inner surface), as shown in FIG. 9A, a 250 ml paper cup 22 used for aseptic filling was prepared by a known method. The PE represents a polyethylene film, and Al represents an aluminum foil. After forming the paper cup, as shown in FIG. 9 (b), 10 @ 4 Bacillus subtilis spores per 10 paper cups were attached to the body pasting part 26 and the heat seal part of the body part 24 and the bottom part 25, and the Bacillus subtilis spores were attached. 200 paper cups adhered were made.
As shown in FIG. 9 (d), 20 μl of 2% H ₂ O ₂ solution 11 diluted with ethyl alcohol was dropped on the paper cup 22 to which the Bacillus subtilis spores 7 were adhered. Then, the paper cup to which the 2% H ₂ O ₂ solution 11 was dropped was put in a corrugated cardboard 8 in a stacked state and packed, and stored at room temperature for 2 days.
As a comparative example, 200 paper cups into which 20 μl of a 2% H ₂ O ₂ aqueous solution was dropped were placed in a cardboard and stored at room temperature for 2 days.

After storing the paper cup in the cardboard for 2 days, take out the paper cup from the cardboard, pour the bouillon agar medium over the heat-sealing part 26, the body 24, and the bottom 25 of the paper cup. Then, the number of viable bacteria was measured by culturing at 35 ° C. for 5 days.
As a result, no viable cell count was observed in any of the paper cups in which the 2% H ₂ O ₂ ethyl alcohol solution was dropped.
However, the paper cup to which the 2% H ₂ O ₂ aqueous solution was dropped was sterilized in the vicinity where the water droplets adhered, but the other parts were not sterilized sufficiently, and 10 to 50 paper cups in 50 out of 200 paper cups. The number of bacteria was detected.

That is, when a 2% H ₂ O ₂ ethyl alcohol solution diluted with ethyl alcohol is dropped into a paper cup, since ethyl alcohol has good permeability, the paper cup body pasting part 26 and the heat seal part of the body part 24 and the bottom part 25 It is considered that H ₂ O ₂ penetrated into the gaps along with ethyl alcohol, and the bacteria attached to the part could be sterilized.
In contrast, in the case of the 2% H ₂ O ₂ aqueous solution, the inner surface of the paper cup is hydrophobic with PE, so the dropped H ₂ O ₂ aqueous solution stays on the surface and does not penetrate into the gap. It is considered that the gap between the body portion 24 and the heat seal portion of the bottom portion 25 results in poor sterilization.
Therefore, the sterilization method using the H ₂ O ₂ solution diluted with a volatile solvent as described above is small, as in the case of a paper cup, on the inner surface of the body pasting portion or the heat sealing portion of the body portion 24 and the bottom portion 25. If there is a gap, it is a very good sterilization method.

  When aseptically filling fruit juice beverages, coffee beverages, other soft drinks, etc. into polyethylene terephthalate bottles (hereinafter referred to as PET bottles) or paper containers, PET bottles, PET bottle preforms, paper containers, etc. It can be used for a sterilization method for sterilizing containers.

It is the schematic diagram which showed the sterilization method of the container of this invention. It is the figure which showed the representative example of containers other than the preform used as the object of the sterilization method of this invention. It is explanatory drawing when the sterilization method of this invention is utilized for preform. It is the figure which showed the process at the time of using the sterilization method of this invention for preform, shape | molding a bottle from the preform, and aseptically filling the bottle. It is explanatory drawing when a bottle is shape | molded using the pre-sterilized preform and the opening part of the bottle is sterilized by ultraviolet rays and aseptically filled. It is the figure which showed the structure of the heat seal part and trunk | drum pasting part of the trunk | drum and bottom part in a paper cup. It is explanatory drawing when utilizing the sterilization method of this invention for a paper cup. FIG. 3 is an explanatory diagram when a preform is sterilized according to Example 1. It is explanatory drawing when a paper cup is sterilized by Example 4. FIG.

DESCRIPTION OF SYMBOLS 1 Preform 2 Bottle 3 Container 4 Lid 5 Cap 6 Aseptic filling product 7 Spore of Bacillus subtilis 8 Corrugated cardboard 9 PE bag 11 H ₂ O ₂ solution 11a H ₂ O ₂ vapor 11b H ₂ O ₂ mist 12 Nozzle for washing water 13 Aseptic Water 14 Filling nozzle 15 Contents 16 Ultraviolet light 17 Ultraviolet irradiation device 20 Container 21 Plastic molding container (deep drawing container)
21a Plastic molding container (injection molding container)
22 Paper cup 23 Cylindrical paper container 23a Square paper container 24 Body part 25 Bottom part 26 Body sticking part 27 Top curl part 28 Laminating material (for paper cup)

Claims (2)

First, using an injection molding machine, a polyethylene terephthalate resin is injection molded to produce a preform,
Next, 30 % to 35% by weight aqueous hydrogen peroxide solution is added to the preform produced above, and the above hydrogen peroxide or hydrogen peroxide aqueous solution is soluble and ethyl alcohol which is a volatile solvent. A 0.1-10% hydrogen peroxide solution diluted with a volatile solvent consisting of methyl alcohol, isopropyl alcohol, or acetone is added dropwise,
Thereafter, the preform in which the hydrogen peroxide solution is dropped is put in a container and sealed with a lid, and the inner surface of the preform is sterilized by the hydrogen peroxide vapor evaporated in the container, and the outer surface of the preform is also removed. A method of sterilizing a preform, characterized by sterilizing. 2. The preform sterilization method according to claim 1, wherein the amount of the hydrogen peroxide solution added per one preform is 0.05 to 100 [mu] l as hydrogen peroxide.