JPH0622532B2 - Manufacturing method of sterilized plastic bottles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a sterilized plastic bottle that is particularly used for filling mineral water.

[Conventional technology]

BACKGROUND ART Conventionally, a plastic bottle such as a polyethylene terephthalate (PET) bottle used for filling mineral water is sterilized by spraying a sterilizing agent such as hydrogen peroxide solution on the inner and outer surfaces of the bottle. However, according to this method, since the germicide remains in the bottle,
There are problems that the flavor of the contents is impaired and that the residue impairs the health of food consumers.

Therefore, various proposals have been made in order to solve such problems. For example, Japanese Patent Laid-Open No. 63-138931 discloses a sterilizing / drying step in which a sterilizing agent is sprayed and then hot air is blown to the container to dry the sterilizing agent, and the sterilizing agent adhering to the inner and outer surfaces of the container is washed and removed. And a cleaning step to perform. Further, JP-A-60-99828 proposes a method of spraying a cleaning liquid after spraying a sterilizing liquid. However, these methods have drawbacks that the bactericide cannot be completely removed unless the amount of the washing solution is increased and the process is messy.

Therefore, there is a need for a method of obtaining a sterilized bottle without using a bactericide.

[Problems to be Solved by the Invention]

Therefore, an object of the present invention is to provide a method capable of easily and efficiently sterilizing a bottle without using a sterilizing agent to produce a sterilized bottle.

[Means for solving the problem]

The present invention discharges hot water into the bottle from the nozzle so that it flows from the bottom wall of the bottle through the side wall and is washed away from the mouth.
This is based on the finding that the above problem can be efficiently solved by raising the temperature of the inner wall of the bottle to the sterilization temperature and heating the outer wall of the bottle to maintain the bottle at the sterilization temperature.

That is, according to the present invention, the hot water injection nozzle is inserted into the inside of the bottle from the mouth of the plastic bottle with the mouth facing downward, and the hot water discharged from the nozzle is transferred from the bottom wall of the bottle to the side wall. Disclosed is a method for producing a sterilized plastic bottle, characterized in that hot water is discharged upward so as to be washed away through the mouth and is heated to raise the temperature of the inner wall of the bottle to the sterilization temperature.

Examples of the bottle to be sterilized in the present invention include blow molded plastic bottles such as polyethylene, polypropylene and polyethylene terephthalate (PET). Of these, PET bottles are particularly preferable for mineral water.

In the present invention, as shown in FIG. 1, the mouth 2 of the bottle 1 is directed downward, preferably right below, and the hot water injection nozzle 3 is inserted into the inside of the bottle from the mouth 2 of the plastic bottle in this state. To do. Then, the hot water 4 is discharged upward so that the hot water 4 flows from the bottom wall 5 of the bottle through the side walls 6 and 6 and is discharged from the mouth 2 to the outside, and the temperature of the inner wall of the bottle is raised to the sterilization temperature. At this time, the hot water injection nozzle 3 is placed inside the bottle 1 so that the tip of the hot water injection nozzle 3 does not come into contact with the hot water W flowing down from the bottom wall 5 of the bottle 1 along the side walls 6, 6. Good to insert. In other words, according to this method, the hot water discharged from the nozzle 3 does not come into contact with the hot water W that comes in contact with the inner wall of the bottle and returns, so that the tip of the hot water injection nozzle is not contaminated. This is because hot water having a predetermined amount of heat can efficiently flow from the bottom wall of the bottle along the side wall. Therefore, according to this method,
The inner wall of the bottle can be stably heated to the sterilization temperature.

Further, when a cylindrical hot water injection nozzle is used, hot water can efficiently flow from the bottom wall to the side wall of the bottle.

In the present invention, the temperature of the inner wall of the bottle is raised to the sterilization temperature by the above method. For example, the inner wall of the bottle is 70 to 90
C., preferably 80 to 85.degree. C. and at least equivalent to the condition that the inner wall is held at 70.degree. C. for 10 seconds, preferably at least 75.degree. C. for 10 seconds, and below the heat-resistant temperature of each bottle. Heat sterilize at the temperature. Incidentally, 7
The condition equivalent to the condition of being kept at 0 ° C. for 10 seconds can be calculated by the following formula.

[In the formula, x is a temperature condition (° C) corresponding to the temperature of the inner wall of the bottle.
And y is the holding time (seconds). The conditions corresponding to 75 ° C. for 10 seconds can be similarly obtained. Generally, since the heat resistant temperature of a plastic bottle is low, such a sterilization condition is preferable because the bottle can be efficiently sterilized without being deformed.

In addition, when the sterilization temperature is lower than 70 ° C. or when the inner wall of the bottle is equal to or less than the condition of being held at 70 ° C. for 10 seconds, a sufficient sterilization effect may not be obtained.

In order to achieve the above sterilization conditions, a cylindrical nozzle having a nozzle inner diameter of 8 to 10 mm, preferably 9 to 10 mm is used as the hot water injection nozzle, and heat at a temperature of 70 ° C. or higher and a temperature lower than the heat resistant temperature of the bottle is used. It is better to inject water. in this case,
It is preferable to use hot water of 75 to 90 ° C. in an amount of 0.2 to 2 times, preferably 0.5 to 1 times the bottle inner volume per bottle. It should be released at a rate. With this, the inner wall of the bottle can be uniformly and efficiently sterilized. As the hot water used for sterilizing the inner wall of the bottle, aseptic water can be used.

In the present invention, in order to further increase the sterilization efficiency, the temperature of the inner wall of the bottle is raised to the sterilization temperature by hot water in the above internal sterilization treatment, and the outer wall of the bottle is heated to keep the bottle at the sterilization temperature for a predetermined time. To do. That is, the temperature of the inner wall of the bottle is raised and maintained at the above sterilization temperature by using the sterilization treatment of the inner wall and the sterilization treatment of the outer wall together. Specifically, it is preferable to heat the outer wall of the bottle by bringing hot water, steam, or hot air into contact with the outer wall of the bottle. In particular, when hot water is used, it is efficient to shower the bottle with hot water from above and / or in the lateral direction. According to this method, the temperature can be easily controlled and the bottle does not deform, which is preferable to the case of using steam or hot air. Further, a method of showering hot water from above the bottle to below is preferable because the hot water can be uniformly transferred to the outer wall of the bottle.

When the external sterilization treatment is performed while the temperature rise of the inner wall of the bottle is maintained by the internal sterilization treatment, the bottle heated to the sterilization temperature by the internal sterilization treatment, for example, the bottle heated to 70 to 90 ° C. This means maintaining the sterilization temperature for a certain period of time.

Specifically, it is preferable to shower hot water of 1 to 100 at 70 to 95 ° C., preferably 75 to 90 ° C. per bottle for 1 to 20 seconds, preferably 3 to 15 seconds. If steam is used instead of hot water, 0.2-0.5 kg /
It is better to blow cm ² (gauge pressure) of steam on the outer wall of the bottle for 3 to 15 seconds, and when using hot air, 80 to
It is advisable to blow hot air at 100 ° C. on the outer wall of the bottle for 3 to 15 seconds.

According to the above method, since the internal sterilization treatment and the external sterilization treatment are used in combination, extremely efficient and complete sterilization can be achieved. In addition, internal sterilization treatment and external sterilization treatment,
Each of the plastic bottles applied under the above-mentioned conditions,
It is preferably used for filling mineral water.

The sterilization treatment can be continuously performed industrially by using, for example, the apparatus 10 shown in FIG. Where 1
Reference numeral 1 denotes a carrier, and the bottle 1 is a hot water injection nozzle 3 for injecting hot water into the inside thereof, and
At 2, the bottle is conveyed in the direction shown while showering hot water from above on the bottle.

The bottle sterilized by the above method can be filled with various liquids, and in particular, mineral water is pumped and then cooled, or the hole diameter after cooling is 0.45 μm.
It can be suitably used when a bottle is filled with mineral water that has been filtered through a filtration membrane of m or less, kept at the above low temperature, and then sterilized. Pore size
It is more preferable to carry out filtration by a filtration membrane of 0.22 μm or less.

〔The invention's effect〕

According to the present invention, a bottle can be sterilized easily and efficiently without using a sterilizing agent. Therefore, when the bottle sterilized by the method of the present invention is used for filling mineral water, the natural flavor of mineral water is not particularly impaired, and sufficient storability can be achieved.

Next, the present invention will be described with reference to examples.

〔Example〕

Example 1 As a plastic bottle, a PE having the same shape as that shown in FIG. 1 and having an inner diameter of 21 mm at the mouth and an internal capacity of 1500 cc
T bottle was used.

Using the above PET bottle, using the device shown in FIG.
Inner washing and outer washing were performed under the following conditions.

(Internal washing process) With the PET bottle mouth facing downward, it is set in the carrier device, and the hot water injection nozzle is introduced into the bottle from the mouth in the circular direction on the front side of FIG. The hot water was inserted and the hot water was discharged upward so that the hot water discharged from the nozzle traveled from the bottom wall of the bottle to the side wall and flowed out from the mouth. In this case, the release process of hot water is 1200 cc of hot water at 85 ° C.
Was discharged from the nozzle at a rate of 13,000 cc / min. A hot water injection nozzle and a cylindrical nozzle having an inner diameter of 9 mm. The inner wall of the bottle is
Hold at ℃ for 3 seconds.

(External washing treatment) Send the PET bottle from the above position to the hot water shower section,
From the upper shower board, 10,000 cc of hot water was showered on the bottle for 5 seconds to carry out an external washing treatment to obtain a PET bottle sterilized microbially stably. The above external washing treatment was started in the latter half of the internal washing treatment.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a state where the inside of a bottle is sterilized by the sterilization method of the present invention, and FIG. 2 is a schematic perspective view of an apparatus for performing the sterilization method of the present invention. . In the figure, 1 is a bottle, 2 is a bottle mouth part, 3 is a hot water injection nozzle, 4 is hot water, and 5 is a bottle bottom wall.

Claims (5)

[Claims] 1. A hot water injection nozzle is inserted into the inside of the bottle from the mouth of a plastic bottle with the mouth facing downward, and hot water discharged from the nozzle causes a bottom wall to a side wall of the bottle. It is characterized in that hot water is discharged upward so as to flow out from the mouth portion and the temperature of the inner wall of the bottle is raised to the sterilization temperature, and the outer wall of the bottle is heated to hold the bottle at the sterilization temperature. A method of manufacturing a sterilized plastic bottle. 2. The hot water injection nozzle is inserted into the bottle so that the tip of the hot water injection nozzle does not come into contact with the hot water flowing down from the bottom wall of the bottle to the side wall of the bottle. Method. 3. A hot water injection nozzle having a nozzle inner diameter of 8 to 1
The method according to claim (1), wherein hot water having a temperature of 70 ° C. or higher and a temperature lower than the heat resistant temperature of the bottle is injected using a 0 mm nozzle. 4. The method according to claim 1, wherein the outer wall of the bottle is heated by bringing hot water, steam or hot air into contact with the outer wall of the bottle. 5. The method according to claim 1, wherein heating of the outer wall of the bottle is performed by showering hot water at a temperature of 70 ° C. or higher and at a temperature lower than the heat resistant temperature of the bottle into the bottle.