JP2005350090A - Method for filling liquid food in thermoplastic resin-made container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for filling a liquid food in a cylindrical thermoplastic resin-made container so that deformation caused by reduced pressure after cooling caused by high-temperature filling is eliminated, and the amount of oxygen in a head space is made to be extremely small, and to provide a liquid food product having excellent appearance which is free from deterioration of the liquid content. <P>SOLUTION: The method for filling the liquid food in the cylindrical thermoplastic resin-made container has a filling step in which the liquid food is filled in the thermoplastic resin-made container having a cylindrical barrel portion in a temperature range of 60-80°C, a liquefied inert gas of the predetermined amount is dripped in the container so that the internal pressure immediately after the sealing is ≥400 kPa, and the internal pressure in a cooled state at 5°C is ≤40 kPa, a cap is hermetically attached thereto. After completing the filling step, the temperature of the liquid content is in a state below 65°C after 10 minutes by cooling. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for filling a liquid food container into a thermoplastic resin container.

  Conventionally, liquid foods such as soy sauce, soy sauce-containing seasonings, vinegar, and cooking liquors have been marketed in glass bottles and other thermoplastic resin containers such as polyethylene terephthalate (hereinafter referred to as PET) bottles. .

  As a method of filling liquid food into a thermoplastic resin container such as a PET bottle, there is a method of filling a container with a content liquid at 60 ° C. to 80 ° C., sealing it with a cap, and cooling it to produce a product.

  Since the liquid food is sold and stored at room temperature, when the high temperature content liquid is filled, the inside of the container is considerably decompressed. For this reason, in order to suppress the depression-like deformation of the container due to the reduced pressure, or to make the deformation inconspicuous, the shape having the reduced-pressure absorption panel 7 or various ribs 8 as shown in Patent Document 1, for example. These so-called heat-resistant PET bottles are used. (See Figure 4)

On the other hand, Patent Document 2 describes a so-called pressure-resistant PET bottle for carbonated beverages having a bottom portion with a shape in which a plurality of legs protrudes. FIG. 5 shows a typical example of a pressure-resistant PET bottle having the petaloid-shaped bottom 4, and a plurality of legs 6 are formed on the bottom 4. FIG. 6 shows another typical example of a pressure-resistant PET bottle used for carbonated beverages. In order to withstand the internal pressure of about 400 kPa caused by foaming liquid, etc., the body 3 is cylindrical and the bottom 4 is formed with a depression 5 like a bottle of champagne, improving the pressure resistance of the bottle itself. In addition, the thread 2a of the mouth tube portion 2 forms a notch portion 2b in order to exert the effect of the gas vent groove that improves the escape of the internal pressure due to the carbon dioxide gas at the time of opening.
Japanese Patent Laid-Open No. 10-58527 JP-A-7-267235

  Here, as described above, in the case of a container for a content liquid that needs to be sterilized, such as a heat-resistant PET bottle, the body portion has a barrel portion like a pressure-resistant PET bottle for carbonated beverages due to the problem of decompression related to high temperature filling. There is a problem that it is not possible to use a cylindrical container having a clean appearance without unevenness such as a vacuum absorbing panel and a rib. There is also a problem that some liquid contents are easily altered by air (oxygen) in the head space.

  Therefore, the present invention was devised to solve the above-described problems in the prior art, and in a cylindrical liquid food container made of thermoplastic resin, the deformation due to reduced pressure after cooling related to high temperature filling is eliminated. It is an object to create a filling method for reducing the amount of oxygen in the head space, and to provide a liquid food product that is excellent in appearance and has no deterioration of contents.

The method of the invention according to claim 1 for solving the technical problem is as follows.
The body is filled with a cylindrical thermoplastic resin container in a temperature range of 60 ° C. to 80 ° C., and the internal pressure immediately after sealing is 400 kPa or less, and is cooled to 5 ° C. Having a filling step in which a predetermined amount of liquefied inert gas is dropped so that the internal pressure becomes 40 kPa or more, and the cap is hermetically mounted;
After completion of the filling process, the content liquid temperature after 10 minutes by cooling is set to a state of less than 65 ° C.,
It is in.

  In the present invention, examples of the liquid food filled in the container include seasonings mainly composed of salt and soy sauce, sauces, mirin, mirin-like seasonings, vinegar, and dressings.

  By setting the filling temperature to a temperature of 60 ° C. or higher by the above method of claim 1, the sterilization effect of the container by the contents liquid and the contents liquid can be expected. Further, when the filling temperature exceeds 80 ° C., the container may be deformed by heat due to the influence of the internal pressure immediately after filling reaching 400 kPa, which will be described later.

  In the present invention, the internal pressure is shown as a differential pressure with respect to the external pressure. For example, the internal pressure of 0 kPa is in balance with the external pressure (normal pressure of 1 atmosphere (approximately 101 kPa)).

  By setting the internal pressure immediately after high-temperature filling to 400 kPa or less from the filling step according to claim 1, for example, as is the case with conventional pressure-resistant PET bottles for carbonated beverages, the wall of the container in particular. It is possible to suppress unauthorized deformation of the container without increasing the thickness of the container, that is, with a wall thickness that can be realized from the standpoint of container productivity, cost reduction, resource saving, and the like.

  In addition, the internal pressure in a state cooled to 5 ° C. is set to a pressurized state of 40 kPa or more with an inert gas, more preferably a pressurized state of 50 kPa or more. Even in cylindrical containers that have the property of being easily deformed by the inward force, it is possible to eliminate the depression of the wall without providing a vacuum absorbing panel, and the loading state during storage or transportation Therefore, it is possible to provide a liquid food product that has a clean appearance and is free from problems such as deformation.

  On the other hand, when the internal pressure is less than 40 kPa, depending on the loading state during transportation, a part of the wall such as the trunk may be deformed due to external force, or the container may be buckled.

  In addition, after filling the content liquid at a high temperature, a predetermined amount of a liquefied inert gas such as liquid nitrogen is dropped to evaporate a part of the liquefied inert gas at the liquid level of the content liquid, so that air present in the head space ( Most of the oxygen) can be easily and efficiently replaced and driven out of the container, so that the oxygen concentration in the headspace can be kept at a low level, and the amount of dissolved oxygen contained in the content liquid is also reduced. be able to.

  Here, the appropriate dripping amount of liquefied inert gas such as liquid nitrogen is the cap from the start of dripping related to the shape of the container, the rigidity of the thermoplastic resin forming the container, and the time to expel the air in the headspace sufficiently. As a matter of course, the higher the internal pressure immediately after filling, the higher the internal pressure in the state cooled to 5 ° C. Because of the one-to-one relationship, it is possible to set a suitable drop amount by experimenting with several drop amount levels.

  In addition, if the container is left for a long time at a temperature equal to or higher than the glass transition temperature after completion of the filling step, the container may be thermally deformed. However, by setting the content liquid temperature after 10 minutes to less than 65 ° C. by the method according to claim 1. This thermal deformation can be prevented. More preferably, the temperature of the content liquid after 10 minutes should be less than 65 ° C., and the temperature of the content liquid after 12 to 15 minutes after completion of the filling process should be 45 ° C. or lower, so that the Deformation can be prevented. Cooling of the content liquid includes means using a cooling medium such as cold water shower, soaking in cold water, and cold air. In addition, when the filling temperature is around 65 ° C., it can be allowed to cool without using a cooling means.

  Here, the time of 10 minutes may include the time used for sterilization of the inner surface of the container and the cap. After filling, the container is turned sideways or upside down, and immediately after filling, the high-temperature content liquid is brought into contact with the inner surface of the cap to sterilize. The time for sterilization is set so that the container and cap are sufficiently sterilized while taking into account the filling temperature of the content liquid, the line speed, etc. Since the cooling time from the partial filling temperature to a temperature lower than 65 ° C. is shortened, it is necessary to quickly cool the content liquid.

  According to a second aspect of the present invention, in the first aspect of the present invention, after the filling step, the content liquid is cooled using a water shower as a cooling medium.

  According to the method of claim 2, the content liquid can be efficiently cooled in a short time. Here, the temperature of the water shower and the time during which the water shower is poured can be appropriately determined in relation to the line speed, the filling temperature of the content liquid, the capacity of the container, and the like.

  According to a third aspect of the present invention, there is provided the method according to the first or second aspect, wherein the thermoplastic resin container is a PET bottle.

  In the above-mentioned method according to claim 3, as a PET bottle, a bottle having a shape like a pressure-resistant PET bottle for carbonated beverages which has been conventionally used can also be used. A pressure-resistant PET bottle basically has a cylindrical body without irregularities due to ribs or the like, does not have a reduced pressure absorption panel, and is so-called a bottom part in which a champagne bottle-like depression is formed or a plurality of legs protrudes. It has a petaloid (petal) -like bottom and has pressure resistance to internal pressure of about 400 kPa.

  The pressure-resistant PET bottle has a shape that is not deformed in a pressurized state, that is, a positive internal pressure, but conversely, a state in which the internal pressure shows a negative value in a reduced pressure state, that is, a force acts from the outside. In some cases, the shape is easily deformed. However, by setting the internal pressure in a state cooled to 5 ° C. with an inert gas to a pressurized state of 40 kPa or more, there is no need to provide a reduced pressure absorption panel. Can be eliminated, and buckling deformation due to a loaded state during storage or transportation can be prevented.

  When the internal pressure in the state cooled to 5 ° C. is less than 40 kPa, depending on the loading state during transportation, a part of the wall such as the trunk portion may be deformed due to an external force, or the bottle may be buckled and deformed. .

  In addition, since it will be in a heating state at the time of content liquid filling, in order to prevent an unauthorized deformation | transformation of a nozzle part, it is preferable to perform heat-resistant processes, such as a whitening process by thermal crystallization, at a nozzle part. In addition, in order to prevent problems such as the content liquid popping out when opening the plug in consideration of the type of the content liquid, usage environment, etc., the mouth tube portion may have a shape having a notch in the thread. .

  In addition, although PET resin is used for the PET bottle used in the present invention, as long as the essence of the PET resin is not impaired, a copolymer polyester containing other polyester units can be used mainly with ethylene terephthalate units, Moreover, in order to improve heat resistance etc., resin, such as nylon resin and a polyethylene naphthalate resin, can also be blended and used.

  Further, the PET bottle used in the present invention is a nylon resin such as PET resin / nylon resin / PET resin so as to improve heat resistance, gas barrier property, etc., as long as the essence as a PET bottle is not impaired. It may have an intermediate layer. Further, a PET bottle having a gas barrier property enhanced by forming a carbon film or a silica compound film on the inner surface or outer surface of the bottle or on the inner and outer surfaces by means of vapor deposition or the like may be used.

  The method of the invention of claim 4 is the method of claim 3, wherein the buckling strength at 5 ° C. is 392.3 N (40 kgf) in a state where the bottle is made of PET and filled with the content liquid and the cap is sealed. ) That's it.

  According to the method described in claim 4, buckling deformation due to a loaded state during storage or transportation can be prevented more reliably. That is, in many cases, PET bottles, for example, are accommodated in a dozen cases, the cases are aligned and stacked on a pallet, and several pallets are stacked or stored or transported, but the buckling strength is 392.3 N (40 kgf ) By doing so, it is possible to reliably prevent the buckling deformation of the PET bottle located at the bottom of the pallet even in the currently used stacking configuration. In addition, the said buckling strength compresses an erect container at the speed | rate of 50 mm / min using the disk of diameter 100mm toward the bottom part from the upper part (mouth side), and when a container buckles. Indicates the value.

  In addition, the requirement for specifying the invention according to claim 4 in which the buckling strength at 5 ° C. is 392.3 N (40 kgf) or more is that the internal pressure in the state of cooling to 5 ° C. in the case of many bottles is 40 kPa or more. However, if the buckling strength is still insufficient, set the internal pressure at 5 ° C higher or change the shape of the bottle or the wall thickness distribution. Is preferably 392.3 N (40 kgf) or more.

The present invention is the method described above, and has the following effects.
In the first aspect of the present invention, by reducing the internal pressure of the liquefied inert gas by dropping it to 5 ° C. and setting it to 40 kPa or more, it is particularly possible to absorb the reduced pressure even if the barrel is a cylindrical container. It is possible to provide a liquid food product that can prevent wall depression without providing a panel, has an unprecedented clean appearance, and has no problems such as deformation.

  In addition, by dripping a predetermined amount of liquefied inert gas such as liquid nitrogen, a part of the liquefied inert gas is vaporized at the liquid level of the content liquid so that substantially the entire amount of air (oxygen) present in the head space is reduced. Since the oxygen concentration in the head space can be made substantially zero by easily and efficiently replacing, alterations relating to the taste, color, etc. of the contents due to oxidation or the like can be kept lower over a long period of time.

  Further, after the filling process, the temperature of the content liquid after 10 minutes is less than 65 ° C., so that the temperature of the content liquid is quickly reduced to a temperature lower than the glass transition temperature of the synthetic resin forming the container. Can be prevented.

  In the invention of claim 2, the content liquid can be efficiently cooled in a short time by using a water shower as a cooling medium.

  In invention of Claim 3, the bottle of the shape of a pressure-resistant PET bottle like for carbonated drinks generally used conventionally can also be used. The pressure-resistant PET bottle has a shape that tends to be deformed by external force or internal decompression. However, by setting the internal pressure in a state of cooling to 5 ° C. to a pressurized state of 40 kPa or more, the vacuum absorbing panel is It is possible to provide a liquid food product using a PET bottle that can eliminate the depression-like deformation of the wall without being provided, has an unprecedented clean appearance, and has no problems such as deformation.

  In the invention according to claim 4, the buckling strength at 5 ° C. of the PET bottle filled with the content liquid and sealed with the cap is set to 392.3 N (40 kgf) or more. Thus, buckling deformation due to the loading state during transportation can be prevented more reliably.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of a PET bottle 1 used in the present invention. A mouth tube portion 2 has a diameter of 28 mmφ and is whitened by a thermal crystallization process, and a body portion 3 has a cylindrical shape. Is formed with a depression 5 like a bottle of champagne.

  FIG. 2 shows that a liquid food such as a soy sauce-containing seasoning is filled at a high temperature with a liquid filling nozzle 13 (a), and a predetermined amount of liquid nitrogen 12 is dropped with a liquid nitrogen supply nozzle 14 to vaporize part of the liquid nitrogen 12. FIG. 5 is an explanatory view schematically showing a filling process in which air existing in the head space 16 is discharged and replaced (b), and the cap 15 is attached in a sealed state (c).

PET with the shape shown in FIG. 1 in the above filling process, with a total height of 204 mm, a barrel maximum diameter of 73.5 mm, and a weight of 32 g, filled with 600 ml of water and with or without liquid nitrogen 12 dripped. An example of the measured value of the amount of oxygen in the bottle 1 is shown below. (The amount of oxygen indicates the volume in the standard state.)
(1) Liquid nitrogen dripping (filling amount 0.11 mg)
0.64ml of oxygen in the headspace
Oxygen content in the content liquid 1.05ml
(2) When there is no dripping of liquid nitrogen Amount of oxygen in the head space 3.90 ml
Oxygen content in the liquid 1.76 ml
From the above (1) and (2), it can be seen that about 84% of oxygen is exhausted in the head space and about 40% in the inner solution.

  After completion of the filling process, for example, the posture of the PET bottle 1 is laid down with the cap 15 attached, or the inner surface of the cap 15 is brought into contact with the inner surface of the cap 15 in an inverted state or the like immediately after filling to perform sterilization. There are cases. When time for this sterilization is necessary, the conditions are set so that the PET bottle 1 and the cap 15 are sufficiently sterilized while taking into account the filling temperature of the content liquid 11, the line speed, and the like.

  Cooling can be efficiently achieved by, for example, pouring a water shower at 50 ° C. or lower. The temperature of the water shower and the cooling time are appropriately determined depending on the line speed, the filling temperature of the contents liquid 11, the time required for starting the cooling including the sterilization time immediately after filling the contents liquid 11, the capacity of the PET bottle 1, etc. I can decide. Moreover, it is not limited to cooling with a water shower, but it is possible to immerse in cold water and use cooling means with cold air. Further, this cooling may be performed by gradually lowering the temperature of the cooling medium or by reducing the temperature of the cooling medium in a multistage manner.

  The graph shown in FIG. 3 is an example of a test result of filling a content liquid at 65 ° C. using a PET bottle for 600 ml (filling amount: 600 ml, head space: about 30 ml). FIG. 5 is a graph in which the internal pressure immediately after mounting the cap 5 is plotted on the horizontal axis, and the vertical pressure is plotted on the vertical axis in the state of being left at room temperature for one day after the cooling step and then left at a temperature of 5 ° C. for one day. This is based on data obtained while appropriately changing the dripping amount. In order to secure an internal pressure of 40 kPa at 5 ° C. from this data, it is necessary to determine the dropping amount of liquid nitrogen so that the internal pressure immediately after filling is approximately 210 kPa or more.

  If the above-described relationship between the pressure immediately after filling and the pressure after cooling is experimentally determined for each shape and filling temperature of the PET bottle 1 to be used by appropriately changing the dropping amount of the liquid nitrogen 12, The dripping amount of the liquid nitrogen 12 for setting the reduced pressure state to a predetermined value can be determined.

Here, an example of calculating the load related to one PET bottle 1 depending on the storage state or the like of the PET bottle 1 during storage or transportation will be shown below.
(1) Premise of calculation a: PET bottle weight per bottle after filling the content liquid 0.64 kg
b: Number of storage units per case: 12 c: Number of loading cases per stage on top of one pallet: 13 units d: Number of cases stacking stage per pallet: 5 steps e: Pallet stacking limit: 4 steps f: Weight of pallet 44kg
(2) Calculation of load Based on the premise of (1), the load related to the bottom PET bottle 1 is (a × b × c × (d × e−1) + f × (e−1). ) / (B × c), and the value is 127.5N (13 kgf), and 382.5N when the safety factor is tripled in consideration of variations in the thickness of the PET bottle or the loading method. (39 kgf).

  In the embodiment described above, the method using a conventional PET bottle having a pressure-resistant PET bottle-like shape has been described. However, the method of the present invention is not limited to the bottle having the shape of this embodiment. Conventionally used PET bottles as shown in FIGS. 7 and 8 can also be used. The PET bottle shown in FIG. 7 has a shoulder portion formed in a stepped shape, and the PET bottle shown in FIG. 8 further has a plurality of peripheral ribs formed on the body portion 3, and the appearance of the bottle is improved along with the improvement in the rigidity of the bottle. It has the purpose of aiming to differentiate itself. Moreover, it is not limited to the product made from PET, For example, it can use also for containers made from thermoplastic resins other than PET.

  A liquid food in a thermoplastic resin container can be provided in a container with an unprecedented clean appearance and in a state in which quality change due to oxidation or the like is further suppressed.

It is a whole front view which shows the PET bottle used for this invention. It is explanatory drawing which shows the outline | summary of the filling method of this invention. It is a graph which shows the relationship between the internal pressure at the time of high temperature filling, and the internal pressure at the time of 5 degreeC cooling. It is a whole front view showing an example of a PET bottle having a reduced pressure absorption panel. It is the whole front view which shows an example of the pressure | voltage resistant PET bottle for carbonated drinks. It is the whole front view which shows the other example of the pressure | voltage resistant PET bottle for carbonated drinks. It is a whole front view which shows the other example of a PET bottle. It is a whole front view which shows another example of a PET bottle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; PET bottle 2; Mouth part 2a; Screw thread 2b; Notch part 3; Trunk part 4; Bottom part 5; Indented part 6; Leg 7; Depressurization absorption panel 8; Rib 11; Content liquid 12; Liquid supply nozzle 14; Liquid nitrogen supply nozzle 15; Cap 16; Head space

Claims (4)

The body is filled with a cylindrical thermoplastic resin container in a temperature range of 60 ° C. to 80 ° C., and the internal pressure immediately after sealing is 400 kPa or less, and is cooled to 5 ° C. Having a filling step in which a predetermined amount of liquefied inert gas is dropped so that the internal pressure becomes 40 kPa or more, and the cap is hermetically attached;
A thermoplastic resin container filling method for liquid food, characterized in that after completion of the filling step, the content liquid temperature after 10 minutes is cooled to a state of less than 65 ° C. The method for filling a liquid food product with a thermoplastic resin container according to claim 1, wherein after the filling step, the liquid content is cooled using a water shower as a cooling medium. The thermoplastic resin container filling method for liquid food according to claim 1 or 2, wherein the thermoplastic resin container is a polyethylene terephthalate bottle. 4. The liquid food according to claim 3, wherein the buckling strength at 5 ° C. of the polyethylene terephthalate bottle with the content liquid filled and the cap sealed is set to 392.3 N (40 kgf) or more. Thermoplastic resin container filling method.

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