JP2006315697A - Plastic bottle for carbonated beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic bottle for carbonated beverage which is capable of holding excellent gas barrier properties even under an environment at a higher temperature than the room temperature. <P>SOLUTION: The plastic bottle is equipped with an inside gas barrier film formed by plasma CVD the inner face side, and the volume increasing ratio under the environment at a higher temperature than the room temperature is 8.0% or less. The volume increasing ratio under the environment at higher temperature than the room temperature has a value obtained by filling carbonated water with a gas volume of 4.2 and after storing it at 40°C for 2 weeks, or a value obtained by filling a carbonated water with a gas volume of 2.8 and after heat treating the central part of a container at 65°C for at least 10 minutes. The gas barrier film is an amorphous carbon film wherein carbon formed by the plasma CVD from a starting raw material containing carbon atom is a main constituent element, or a silicon oxide-containing film formed from a starting raw material including an organosilicone compound and having an atomic Si/O ratio of 1/1.5-1/2.2. The plastic bottle is a polyester bottle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plastic bottle for carbonated beverages.

  Conventionally, a plastic bottle formed by biaxially stretching blow-molding a preform made of plastic such as polyethylene terephthalate is known. The plastic bottle is excellent in mechanical strength, transparency and the like, and is harder to break than a glass container and light in weight. Therefore, the plastic bottle is used in various applications and widely used as a beverage filling bottle. .

  However, the plastic bottle has a problem that the gas barrier property is lower than that of a metal container or a glass container, and gas such as oxygen and carbon dioxide gas is easily transmitted. For example, in a small-capacity plastic bottle whose consumption has been increasing in recent years, since the ratio of the surface area to the content liquid amount is large, the effect of gas permeation on the content quality is large. Then, the expiration date may become extremely short. Therefore, in order to improve the gas barrier property of the plastic bottle, a plastic bottle in which a gas barrier film such as an amorphous carbon film or a silicon oxide-containing film is formed on the inner surface side has been proposed (for example, see Patent Document 1).

  The gas barrier coating is, for example, arranging the plastic bottle in a hollow processing chamber, inserting a raw material gas introduction pipe into the inside from the plastic bottle mouth, and exhausting the inside of the processing chamber and the plastic bottle to a vacuum, It can be formed by a method (plasma CVD method) in which plasma is generated by supplying a source gas and applying a high frequency or microwave voltage.

  By forming the gas barrier coating on the inner surface side of the plastic bottle, it is possible to extremely reduce the permeation of carbon dioxide gas from the wall surface of the bottle. Such plastic bottles for carbonated drinks are filled with pressure-resistant bottles used for filling carbonated drinks such as cider and cola at a low temperature of about 5 ° C, and carbonated drinks with fruit juice at a low temperature of about 5 ° C. After that, there is a heat and pressure bottle used for the purpose of heat sterilization by holding the container center at a temperature of 65 ° C. for 10 minutes or more. The heat sterilization treatment is usually performed by applying a hot water shower at about 66 ° C. to the heat-resistant pressure bottle for 30 to 40 minutes.

However, in the pressure-resistant bottle formed with the gas barrier coating, when filled with the carbonated beverage, the gas barrier property is reduced in an environment where the temperature is higher than room temperature, such as when it is displayed at a storefront in summer or stored in a warehouse. Therefore, there is a disadvantage that the carbon dioxide in the carbonated beverage is easily released and the commercial value is lowered. Further, in the heat and pressure bottle formed with the gas barrier coating, the gas barrier property is lowered in an environment higher than room temperature such as heat sterilization after filling the carbonated beverage containing fruit juice, and the carbon dioxide gas in the carbonated beverage is released. There is an inconvenience that it becomes easier and the commercial value is lowered.
JP 2004-142743 A

  The present invention eliminates such inconvenience and maintains excellent gas barrier properties even in an environment higher than room temperature, such as store display in the summer, storage in a warehouse, or heat sterilization after filling with a carbonated beverage containing fruit juice. An object of the present invention is to provide a plastic bottle for carbonated beverages.

  The present inventors, when filled with carbonated beverages in the plastic bottle formed with the gas barrier coating, store higher than room temperature, such as store display in the summer, storage in the store, or heat sterilization treatment after filling with carbonated beverages containing fruit juice As a result of examining the reason why the gas barrier property is lowered in the environment of the above, when the bottle internal pressure increases in the environment higher than the room temperature, and the bottle volume expands beyond a certain amount, the gas barrier It has been found that the performance is lowered. When the volume of the plastic bottle expands, an amorphous carbon coating or a silicon oxide-containing coating forming the gas barrier coating generates a fine defect that cannot be visually discerned, and oxygen in the portion where the defect has occurred, It seems that gas such as carbon dioxide gas is easy to permeate.

  Therefore, in order to achieve the above object, the present invention provides a plastic bottle for carbonated beverages having a gas barrier coating formed by plasma CVD on the inner surface side, and has a volume increase rate of 8.0% in an environment higher than room temperature. It is characterized by the following. In the present invention, the volume increase rate in an environment higher than the room temperature is a value after filling with carbonated water having a gas volume of 4.2 and storing at a temperature of 40 ° C. for 2 weeks, or a carbon dioxide having a gas volume of 2.8. It is a value after performing a heat treatment that fills water and holds the center of the container at a temperature of 65 ° C. for 10 minutes or more.

  The condition “After filling with carbonated water with a gas volume of 4.2 and storing for 2 weeks at a temperature of 40 ° C.” is equivalent to a plastic bottle filled with a carbonated beverage containing the highest level of carbon dioxide in the summer. Stricter conditions are set for the storefront display and warehouse storage during the period. In addition, carbonated beverages with fruit juice require sterilization by heat treatment that keeps the center of the container at a temperature of 65 ° C. for 10 minutes or longer after filling, but the gas volume of carbonated beverages with fruit juice is usually maximum. It is about 2.8.

  According to the plastic bottle for carbonated beverages of the present invention, the volume increase rate under the environment higher than the room temperature is 8.0% or less, so that excellent gas barrier properties are maintained even under the environment higher than the room temperature. The content of carbon dioxide in the contents can be maintained, and oxygen can be prevented from entering, thereby preventing a decrease in commercial value. On the other hand, if the volume increase rate in the environment higher than the room temperature exceeds 8.0%, the gas barrier property is lowered, and it becomes impossible to prevent the content of carbon dioxide gas in the contents from being lowered and the invasion of oxygen. .

  The gas barrier film has an amorphous carbon film mainly containing carbon formed by plasma CVD from a starting material containing carbon atoms, or an Si / O ratio formed by plasma CVD from a starting material containing an organosilicon compound. It is a silicon oxide-containing film in an atomic ratio range of 1 / 1.5-1 to 2.2.

  Examples of the plastic bottle include a polyester bottle made of polyester such as polyethylene terephthalate.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory cross-sectional view showing a configuration example of a CVD apparatus used for manufacturing a plastic bottle for carbonated beverages of the present embodiment.

  The plastic bottle for carbonated beverages of the present embodiment is, for example, a pressure-resistant bottle or heat-resistant pressure bottle obtained by blow molding a preform made of a polyester resin, and alcoholic beverages containing carbonate such as beer and sparkling liquor, soda water It is used as a container for soft drinks containing carbonic acid such as cider, cola, and carbonated drink containing fruit juice. The plastic bottle for carbonated beverages has a gas barrier coating formed on the inner surface side thereof in order to prevent carbon dioxide in the beverage from evaporating to the outside of the bottle and oxygen in the air from entering the inside of the bottle.

  The pressure bottle has a volume increase rate of 8.0% or less after being stored for 2 weeks at a temperature of 40 ° C. and filled with water of a gas volume of 4.2 assuming long-term store display and storage in the summer. It has become. In the heat and pressure bottle, the volume increase rate after filling with carbonated water with a gas volume of 2.8 and holding the center of the container at a temperature of 65 ° C. for 10 minutes or more is 8.0% or less. It has become.

  As a result, the plastic bottle for carbonated beverages is used for the carbonated beverages in beverages in an environment where the temperature is higher than room temperature such as long-term store display in the summer, storage in a warehouse, or heat sterilization after filling with carbonated beverages containing fruit juice. Therefore, even if the bottle internal pressure increases and the volume of the bottle expands, the gas barrier property of the gas barrier coating can be maintained.

  The polyester resin forming the plastic bottle for carbonated beverages is a resin obtained by a condensation polymerization reaction, a transesterification reaction or the like of a polyhydric alcohol and a polyvalent carboxylic acid compound. Examples of such a polyester resin include polyethylene terephthalate resin, polybutylene terephthalate, and polyethylene naphthalate. In the present embodiment, a case where the plastic bottle is a polyethylene terephthalate resin bottle (hereinafter abbreviated as a PET bottle) will be described as an example.

  The PET bottle for carbonated beverages is manufactured by first blow-molding a preform made of polyethylene terephthalate resin to produce a pressure-resistant bottle or heat-resistant pressure bottle as a base bottle, and forming the gas barrier coating on the inner surface side of the base bottle Can be manufactured.

  At this time, as a method for manufacturing the base bottle for suppressing the volume increase rate in the environment higher than the room temperature, for example, the resin amount of the preform is increased to thicken the side wall of the base portion of the base bottle. There is a way.

  Also, when a preform bottle is blow molded to produce a base bottle, the molecular chain is tensioned by giving a high degree of biaxial molecular orientation to the shoulder and torso, and at the same time, crystallization progresses to significantly improve the pressure resistance. Therefore, it is desirable to set the stretch ratio at the time of blow molding to a high value within a range where pearl color due to overstretching does not occur.

  At this time, if the heating temperature of the preform is too high, the tension of the molecular chain is relaxed and the expansion due to the internal pressure increases, and the thickness distribution tends to be uneven. It is desirable to set it low so as not to generate pearl color due to stretching.

  On the other hand, when the mold temperature at the time of blow molding is too low, the shrinkage with time of the bottle increases due to residual distortion due to rapid cooling, and as a result, the volume expansion rate after filling with carbonated water may increase.

  Therefore, in consideration of these, by appropriately combining molding conditions including the preform design (mass, draw ratio), preform heating temperature, blow mold temperature, etc., in an environment higher than the room temperature. A base bottle for suppressing the volume increase rate can be manufactured.

  In addition, the preform is once blow-molded into a bottle with a volume larger than the target base bottle, then heated and shrunk, and blow-molded again to obtain the target base bottle. Is unnecessarily thick and can be avoided from becoming thin from the shoulder to the body, while at the same time improving the crystallinity of the side walls and increasing the rigidity, increasing the volume in an environment higher than room temperature. It can use suitably for the use which manufactures the base bottle for suppressing a rate.

  The said PET bottle for carbonated drinks provided with the said gas barrier film in the inner surface side of the said base bottle can be manufactured with the plasma CVD apparatus 1 of FIG. 1, for example.

  In FIG. 1, a plasma CVD apparatus 1 includes a processing chamber 4 in which a microwave introduction part is defined by a side wall 2 formed of Pyrex (registered trademark) glass and a bottom plate 3 that can be moved up and down, and faces the side wall 2. A microwave generator 5 is provided at the position. An exhaust chamber 8 defined by a side wall 6 and an upper wall 7 is provided above the processing chamber 4, and a partition wall 9 is provided between the processing chamber 4.

  The base plate 3 accommodates the base bottle 10 in the processing chamber 4 by arranging the base bottle 10 and moving upward. The base bottle 10 stored in this way is arranged so that the inside of the bottle communicates with the exhaust hole 12 provided in the partition wall 9 through the mouth holder 11. In the mouth holder 11, the upper protrusion 13 is closely inserted into the exhaust hole 12, and the mouth holder 14 is inserted into the mouth of the base bottle 10 at a predetermined interval.

  The processing chamber 4 and the exhaust chamber 8 communicate with each other through a valve 16 of a vent 15 provided in the partition wall 9, and an opening 17 formed in the side wall 6 of the exhaust chamber 8 is connected to a vacuum device (not shown). Yes. A gas introduction pipe 19 for supplying a gaseous starting material (hereinafter abbreviated as a raw material gas) is supported on the upper wall 7 of the exhaust chamber 8 via a seal 18, and the gas introduction pipe 19 is supported on the upper wall 7. And the mouthpiece holder 11 are inserted into the base bottle 10. There is a gap between the gas introduction pipe 19 and the inner peripheral surface of the mouth holder 11.

  In the plasma CVD apparatus 1 shown in FIG. 1, first, the bottom plate 3 on which the base bottle 10 is placed is moved up and the base bottle 10 is accommodated in the processing chamber 4. Next, a vacuum device (not shown) is operated to evacuate the exhaust chamber 8, thereby reducing the pressure inside the processing chamber 4 through the vent 15. At the same time, the inside of the base bottle 10 is depressurized to a predetermined degree of vacuum through the gap between the gas introduction pipe 19 inserted into the exhaust hole 12 and the inner peripheral surface of the mouth holder 11.

  Next, the source gas is supplied from the gas introduction pipe 19 into the base bottle 10. In the plasma CVD apparatus 1, the raw material gas is continuously supplied and continuously exhausted by the vacuum apparatus, and the inside of the processing chamber 4 and the base bottle 10 is maintained at a predetermined degree of vacuum. The supply amount of the source gas is set to an appropriate amount according to the surface area of the target base bottle 10 and the thickness of the coating film to be formed.

  Then, while the source gas is being supplied, the microwave generator 5 is operated to irradiate the microwave with a predetermined frequency and a predetermined output for a predetermined time, thereby electromagnetically exciting the source gas 10 Plasma is generated therein, and a gas barrier film (not shown) is formed on the inner surface of the base bottle 10.

  Next, when the supply of the raw material gas is completed, the microwave generator 5 is stopped, the inside of the processing chamber 4 and the base bottle 10 is returned to atmospheric pressure, the bottom plate 3 is lowered, and the base bottle 10 is removed. The processing is terminated by taking out. The microwave generator 5 may be stopped at the same time as the supply of the source gas is completed, but may be irradiated for a short time. By doing so, the raw material gas component remaining in the container can be completely formed into a film, and the gas barrier property of the obtained bottle 10 and the flavor retention property when the contents are filled are further improved. be able to.

  Next, the case where an amorphous carbon film having carbon as a main constituent element is formed as the gas barrier film will be described.

  First, the raw material gases used include aliphatic unsaturated hydrocarbon compounds such as acetylene, ethylene, and propylene, aliphatic saturated hydrocarbon compounds such as methane, ethane, and propane, alicyclic hydrocarbon compounds such as cyclohexane, benzene, and toluene. Carbon-containing compounds such as aromatic hydrocarbon compounds such as xylene can be used. The source gas may be used alone or as a mixture of two or more as required. A small amount of hydrogen, an organosilicon compound, and other film-forming organic compounds are used in combination as a film modifier. Also good. The source gas may be diluted with a rare gas such as argon or helium.

  However, in order to form an amorphous carbon thin film, which is a coating having excellent gas barrier properties, in a shorter time, it is suitable that the source gas is substantially acetylene, preferably 60% by volume or more of the source gas, preferably 80% by volume or more is acetylene. When the source gas is substantially composed of acetylene, the acetylene may contain inevitable impurities mixed in during the production process.

In order to form the amorphous carbon film having a film thickness of 0.007 to 0.08 μm on the base bottle 10 having an internal volume of 200 to 2000 ml, the supply amount of the source gas is 0.1 to 0.1 per surface area in the container. A range of 0.8 sccm / cm ² is suitable.

  The operating condition of the microwave generator 5 while the raw material gas is supplied is, for example, a microwave with a frequency of 2.45 GHz and an output of 150 to 600 W for 0.2 to 2.0 seconds, preferably 0.4 to It shall be irradiated for 1.5 seconds. As a result, the source gas is electromagnetically excited to generate plasma in the base bottle 10, and an amorphous carbon film (not shown) is formed on the inner surface of the base bottle 10.

  At this time, it is desirable that the vacuum in the base bottle 10 is maintained at 1 to 50 Pa by continuously exhausting the vacuum with the vacuum device while continuously supplying the source gas. When the degree of vacuum is less than 1 Pa, it takes a long time to form the amorphous carbon coating, and when it exceeds 50 Pa, the adhesion, workability, and gas barrier properties of the amorphous carbon coating to the inner surface of the base bottle 10 are degraded.

  When the microwave output is less than 150 W, the formed coating may be highly colored, and when it exceeds 600 W, the oxygen permeability may be increased. In addition, when the microwave irradiation time is less than 0.2 seconds, a desired film thickness may not be obtained in the amorphous carbon film, and when it exceeds 2.0 seconds, the film thickness of the amorphous carbon film is increased. And coloring may become darker.

  Next, the case where a silicon oxide containing film is formed as the gas barrier film will be described.

  First, as source gases to be used, silanes such as silane, alkylsilane, dialkylsilane, and trialkylsilane, alkoxysilanes such as monoalkoxysilane, dialkoxysilane, and trialkoxysilane, tetraalkyldisiloxane, and hexaalkyldisiloxane In addition to siloxanes such as hexamethyldisilazane, etc., known organic silicon compound gases can be used. The raw material gases may be used alone or as a mixture of two or more as necessary, and oxygen gas is preferably mixed and used at an appropriate ratio. When an organosilicon compound having a high carbon content is used as the source gas, it is preferable to increase the mixing ratio of oxygen gas in order to remove carbon as carbon dioxide. The source gas may be diluted with a rare gas such as argon or helium.

  When other gas such as oxygen gas or rare gas is used together with the organosilicon compound gas as the source gas, the organosilicon compound gas and other gas are mixed in advance from the gas introduction pipe 19. Alternatively, two gas introduction pipes 19 may be provided, and the gas of the organosilicon compound may be introduced from one of them, and another gas may be introduced from the other one. Alternatively, the gas introduction pipes 19 may be provided in an inner and outer double so that the gas of the organosilicon compound is introduced from one side of the inner side or the outer side, and another gas is introduced from the other side. However, when two gas introduction pipes 19 are provided, or when the gas introduction pipes 19 are provided in an inner and outer double, care must be taken that the organosilicon compound and other gases are sufficiently mixed. .

In this case, the degree of vacuum inside the base bottle 10 is preferably 10 ⁻¹ to 10 ² Pa. When the degree of vacuum is less than 10 ⁻¹ Pa, it takes a long time to form the silicon oxide-containing coating, and when it exceeds 10 ² Pa, the adhesion, workability, and gas barrier of the silicon oxide-containing coating to the inner surface of the base bottle 10 Sexuality decreases.

  The operating conditions of the microwave generator 5 while the raw material gas is being supplied vary depending on the internal volume of the base bottle 10, the type and composition of the raw material gas, etc., for example, with a frequency of 2.45 GHz and an output of 100 to 3000 W. The microwave is irradiated for 1 to 30 seconds, preferably 3 to 10 seconds. As a result, the source gas is electromagnetically excited to generate plasma in the base bottle 10, and the Si / O ratio is within the range of 1 / 1.5 to 1 / 2.2 in atomic ratio on the inner surface of the base bottle 10. A silicon oxide film (not shown) having a thickness of 3 to 100 nm is formed.

  Next, examples of the present invention and comparative examples will be described.

  In this example, first, a preform made of polyethylene terephthalate resin having a mass of 32 g was used, blow molding was performed by appropriately setting the preform heating temperature, blow mold temperature, stretch ratio, wall thickness distribution, etc. As a result, a pressure-resistant bottle having an internal volume of 500 ml was manufactured.

  Next, an amorphous carbon film having a thickness of about 35 nm was formed on the inner surface side of the base bottle by the CVD apparatus 1 shown in FIG. The amorphous carbon coating was formed by supplying acetylene as a raw material gas while maintaining the interior of the base bottle 10 at 5 Pa, and irradiating microwaves with a frequency of 2.45 GHz and an output of 260 W for a short time.

  As a result, a carbonated beverage PET bottle having a volume increase rate of 5.5% after being stored for 2 weeks at 40 ° C. after filling the carbonated water with a gas volume of 4.2 by replacing the head space with carbon dioxide gas. Obtained. The volume increase rate was measured as follows.

First, the container which accommodated the quantity of water which can sink the PET bottle for carbonated drinks obtained by the present Example was arrange | positioned on the balance. Next, after filling the PET bottle for carbonated drink obtained in this example with a full amount of water, a cap is attached, and the bottle is placed on the inner surface of the container in the water contained in the container arranged on the balance. The volume (V ₁ ) of the carbonated beverage PET bottle containing the content liquid was determined from the weight difference between before and after sinking completely without contact.

Next, after discharging water from the PET bottle for carbonated beverages, the carbonated water of gas volume 4.2 was filled by replacing the head space with carbon dioxide gas, and stored at 40 ° C. for 2 weeks. While maintaining the temperature, the bottle is completely submerged in water accommodated in a container placed on the balance so as not to contact the inner surface of the container. The volume (V ₂ ) of the PET bottle for carbonated beverages was determined. And the volume increase rate was calculated | required by following Formula.

Volume increase rate (%) = ((V ₂ −V ₁ ) / V ₁ ) × 100
In addition, the carbonated beverage PET bottle obtained in this example was filled with carbonated water with a gas volume of 4.2 by replacing the headspace with carbon dioxide gas, and stored at 40 ° C. for 2 weeks, and at 40 ° C. After storing for 4 weeks, the gas volume of carbonated water in each bottle was measured, and the amount of decrease in carbon dioxide gas was determined from the difference from the gas volume immediately after filling. The gas volume was measured using a gas volume measuring device (trade name: VAG-500) manufactured by Kyoto Electronics Industry Co., Ltd. after cooling the bottle filled with carbonated water to about 6 ° C.

  Moreover, the oxygen transmission rate before filling the carbonated water of the PET bottle for carbonated beverages obtained in this example and the oxygen transmission rate after storing for 4 weeks at 40 ° C. after filling the carbonated water were measured. The measurement of the oxygen transmission rate was performed under the conditions of 22 ° C. and relative humidity 60% using OXTRAN 2/20 (trade name) manufactured by MOCON.

  The results are shown in Table 1.

  In this example, a silicon oxide-containing film having a thickness of about 30 nm was formed on the inner surface side of the base bottle by the CVD apparatus 1 shown in FIG. 1 using the base bottle manufactured in Example 1. The silicon oxide-containing film is formed by reducing the inside of the processing chamber 4 and the base bottle 10 to a predetermined degree of vacuum, and then supplying an organic silicon compound gas and oxygen as a raw material gas, with a frequency of 2.45 GHz, It was carried out by irradiating microwaves with an output of 1500 W for a short time.

  As a result, a carbonated beverage PET bottle having a volume increase rate of 5.4% after being stored for 2 weeks at 40 ° C. after filling the carbonated water with a gas volume of 4.2 by replacing the head space with carbon dioxide gas. Obtained. The volume increase rate was measured in the same manner as in Example 1.

Next, except that the carbonated beverage PET bottle obtained in this example was used, exactly the same as in Example 1, the amount of carbon dioxide gas in the carbonated water in the carbonated beverage PET bottle, and the carbonated beverage The oxygen transmission rate of the PET bottle for medical use was measured. The results are shown in Table 1.
[Comparative Example 1]
In this comparative example, the base bottle manufactured in Example 1 was filled with carbonated water having a gas volume of 4.2 without replacing the headspace with carbon dioxide gas at 40 ° C. without forming a gas barrier coating at all. A PET bottle for carbonated drink having a volume increase rate of 5.7% after storage for 2 weeks was obtained. The volume increase rate was measured in the same manner as in Example 1.

Next, except for using the carbonated beverage PET bottle obtained in this comparative example, exactly the same as in Example 1, the amount of carbon dioxide gas in the carbonated water in the carbonated beverage PET bottle, and the carbonated beverage The oxygen transmission rate of the PET bottle for medical use was measured. The results are shown in Table 1.
[Comparative Example 2]
In this comparative example, although it is the same mass (32g) as the base bottle manufactured in Example 1, the pressure-resistant PET bottle having a lower body stretch ratio than the preform used in Example 1 was used as the base bottle. Except for the above, an amorphous carbon film having a film thickness of about 35 nm was formed on the inner surface side of the base bottle in exactly the same manner as in Example 1. As a result, a carbonated beverage PET bottle with a volume increase rate of 9.4% after being stored for 2 weeks at 40 ° C. after filling the carbonated water with a gas volume of 4.2 by replacing the head space with carbon dioxide gas. Obtained. The volume increase rate was measured in the same manner as in Example 1.

Next, except for using the carbonated beverage PET bottle obtained in this comparative example, exactly the same as in Example 1, the amount of carbon dioxide gas in the carbonated water in the carbonated beverage PET bottle, and the carbonated beverage The oxygen transmission rate of the PET bottle for medical use was measured. The results are shown in Table 1.
[Comparative Example 3]
In this comparative example, first, a preform made of polyethylene terephthalate resin having a mass of 24 g was blow-molded in a mold to produce a pressure-resistant bottle having an internal capacity of 500 ml as a base bottle.

  Next, an amorphous carbon film having a thickness of about 35 nm was formed on the inner surface side of the base bottle in exactly the same manner as in Example 1 except that the base bottle obtained in this comparative example was used. As a result, a carbonated beverage PET bottle having a volume increase rate of 10.7% after being stored for 2 weeks at 40 ° C. after filling the carbonated water with a gas volume of 4.2 by replacing the head space with carbon dioxide gas. Obtained. The PET bottle for carbonated beverages of this comparative example has a smaller mass of the preform than that of Example 1, and as a result, the side wall is thin, so the volume increase rate exceeds 7%. It seems to have been. The volume increase rate was measured in the same manner as in Example 1.

  Next, except for using the carbonated beverage PET bottle obtained in this comparative example, exactly the same as in Example 1, the amount of carbon dioxide gas in the carbonated water in the carbonated beverage PET bottle, and the carbonated beverage The oxygen transmission rate of the PET bottle for medical use was measured. The results are shown in Table 1.

表１から、内面側にガスバリア被膜を備え、ガスボリューム４．２の炭酸水を充填し、４０℃で２週間保存後の体積増加率が８．０％以下である実施例１，２の炭酸飲料用ＰＥＴボトルによれば、前記充填から４週間後でも酸素透過量によって示される酸素バリア性が０．０１５ｍｌ／ボトル／日以下と良好であり、前記炭酸水中の炭酸ガス減少量も少なく、夏期等の店頭陳列や倉庫保存等の室温より高温の環境下でも、優れたガスバリア性を保持していることが明らかである。

From Table 1, the carbon dioxide of Examples 1 and 2 having a gas barrier coating on the inner surface, filled with carbonated water having a gas volume of 4.2, and having a volume increase rate of 8.0% or less after storage at 40 ° C. for 2 weeks. According to the PET bottle for beverages, the oxygen barrier property indicated by the oxygen permeation amount is good at 0.015 ml / bottle / day or less even after 4 weeks from the filling, and the amount of carbon dioxide in the carbonated water is small, and the summer It is apparent that excellent gas barrier properties are maintained even in an environment where the temperature is higher than room temperature such as store display or storage in a warehouse.

  In contrast, a carbonated beverage PET bottle filled with carbonated water having a gas volume of 4.2 and having a volume increase rate of 8.0% or less after being stored at 40 ° C. for 2 weeks (without comparison) Example 1) PET bottle for carbonated beverages with a gas barrier coating but filled with carbonated water with a gas volume of 4.2 and having a volume increase rate of more than 8.0% after storage at 40 ° C. for 2 weeks (Comparative Example) 2 and 3), it is clear that both oxygen permeation amount and carbon dioxide gas decrease amount after 4 weeks from the filling are larger than those in Examples 1 and 2.

  In this example, first, a preform of polyethylene terephthalate resin having a mass of 28 g is used, blow molding is performed with appropriate settings of thickness distribution, heat setting conditions, etc., and a heat-resistant pressure bottle with an internal capacity of 350 ml is produced as a base bottle. did.

  Next, an amorphous carbon film having a thickness of about 50 nm was formed on the inner surface side of the base bottle by the CVD apparatus 1 shown in FIG. The amorphous carbon film is formed by depressurizing the interior of the processing chamber 4 and the base bottle 10 to a predetermined degree of vacuum, supplying acetylene as a source gas, and applying microwaves with a frequency of 2.45 GHz and an output of 380 W for a short time. Performed by irradiation.

  As a result, the carbonated beverage containing fruit juice with a gas volume of 2.8 is filled by replacing the head space with carbon dioxide, and the center of the container is maintained at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes. Thus, a PET bottle for carbonated beverages having a volume increase rate of 3.4% after the heat sterilization treatment was obtained. The volume increase rate was measured in the same manner as in Example 1.

  Next, a carbonated beverage containing fruit juice with a gas volume of 2.8 was filled in the PET bottle for carbonated beverage obtained in this example by replacing the head space with carbon dioxide gas, and the center of the container was obtained by hot water shower for 35 minutes. The portion is kept at a temperature of 65 ° C. for 10 minutes or longer and then heat sterilized, and further stored at 40 ° C. for 2 weeks. The amount of carbon dioxide reduction in the carbonated beverage containing fruit juice after storage was measured. Moreover, the oxygen transmission rate immediately after the filling of the PET bottle for carbonated beverages and the oxygen transmission rate after storage at 40 ° C. for 4 weeks were measured. The amount of carbon dioxide reduction and the oxygen transmission rate were measured in the same manner as in Example 1. The results are shown in Table 2.

  In this example, the base bottle manufactured in Example 3 was used, and a silicon oxide film having a thickness of about 30 nm was formed on the inner surface side of the base bottle by the CVD apparatus 1 shown in FIG. The silicon oxide film is formed by irradiating a microwave with a frequency of 2.45 GHz and an output of 1000 W for a short time while supplying the organic silicon compound and oxygen as source gases while maintaining the interior of the base bottle 10 at 30 Pa. Was done.

  As a result, the carbonated beverage containing fruit juice with a gas volume of 2.8 is filled by replacing the head space with carbon dioxide, and the center of the container is maintained at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes. Thus, a PET bottle for carbonated beverages having a volume increase rate of 3.3% after the heat sterilization treatment was obtained. The volume increase rate was measured in the same manner as in Example 1.

Next, except using the carbonated beverage PET bottle obtained in this example, exactly the same as in Example 3, the amount of carbon dioxide gas in the carbonated beverage containing fruit juice in the carbonated beverage PET bottle, The oxygen transmission rate of the carbonated beverage PET bottle was measured. The results are shown in Table 2.
[Comparative Example 4]
In this comparative example, the base bottle manufactured in Example 3 was filled with a carbonated beverage containing fruit juice having a gas volume of 2.8 without replacing any gas barrier coating, replacing the headspace with carbon dioxide gas, for 35 minutes. A PET bottle for carbonated beverages having a volume increase rate of 3.9% after heat sterilization treatment was performed so that the center of the container was kept at a temperature of 65 ° C. for 10 minutes or more by a hot water shower. The volume increase rate was measured in the same manner as in Example 1.

Next, except for using the carbonated beverage PET bottle obtained in this Comparative Example, exactly the same as Example 3, the amount of carbon dioxide reduction in the carbonated beverage containing fruit juice in the carbonated beverage PET bottle, The oxygen transmission rate of the carbonated beverage PET bottle was measured. The results are shown in Table 2.
[Comparative Example 5]
In this comparative example, a heat-resistant pressure PET bottle was manufactured in exactly the same manner as in Example 3 except that the preform heating temperature was high and the thickness distribution was slightly non-uniform. Next, a silicon oxide film having a thickness of about 30 nm is formed on the inner surface of the base bottle in exactly the same manner as in Example 4 except that the heat-resistant pressure PET bottle obtained in this comparative example is used as a base bottle. did. As a result, the carbonated beverage containing fruit juice with a gas volume of 2.8 is filled by replacing the head space with carbon dioxide, and the center of the container is maintained at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes. Thus, a PET bottle for carbonated beverages having a volume increase rate of 9.8% after the heat sterilization treatment was obtained. The volume increase rate was measured in the same manner as in Example 1.

  Next, except for using the carbonated beverage PET bottle obtained in this Comparative Example, exactly the same as Example 3, the amount of carbon dioxide reduction in the carbonated beverage containing fruit juice in the carbonated beverage PET bottle, The oxygen transmission rate of the carbonated beverage PET bottle was measured. The results are shown in Table 2.

表２から、内面側にガスバリア被膜を備え、ガスボリューム２．８の果汁入り炭酸飲料を充填し、３５分間の熱水シャワーにより容器中心部が６５℃の温度に１０分間以上保持されるようにして加熱殺菌処理を行った後の体積増加率が８．０％以下である実施例３，４の炭酸飲料用ＰＥＴボトルによれば、前記充填から４週間後でも酸素透過量によって示される酸素バリア性が０．０１５ｍｌ／ボトル／日以下と良好であり、前記果汁入り炭酸飲料中の炭酸ガス減少量も少なく、前記果汁入り炭酸飲料を充填した後の加熱殺菌処理等における室温より高温の環境下でも、優れたガスバリア性を保持していることが明らかである。

From Table 2, a gas barrier coating is provided on the inner surface side, filled with a carbonated beverage containing fruit juice with a gas volume of 2.8, and the center of the container is kept at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes. According to the PET bottles for carbonated beverages of Examples 3 and 4 having a volume increase rate of 8.0% or less after the heat sterilization treatment, the oxygen barrier indicated by the oxygen permeation amount even after 4 weeks from the filling In an environment at a temperature higher than room temperature in a heat sterilization treatment or the like after filling the carbonated beverage with fruit juice, and the like is less than 0.015 ml / bottle / day. However, it is clear that excellent gas barrier properties are maintained.

  On the other hand, a carbonated beverage containing fruit juice with a gas volume of 2.8 was filled, and a heat sterilization treatment was performed so that the center of the container was kept at a temperature of 65 ° C. for 10 minutes or more by a hot water shower for 35 minutes. PET bottles for carbonated beverages having a volume increase rate of 8.0% or less but not having a gas barrier coating (Comparative Example 4), and carbonated beverages containing fruit juice having a gas volume of 2.8 but having a gas barrier coating PET for carbonated beverages with a volume increase rate of more than 8.0% after filling and heat sterilization by keeping the container center at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes In the bottle (Comparative Example 5), it is clear that both the oxygen permeation amount after 4 weeks from the filling and the carbon dioxide gas reduction amount in the carbonated beverage containing fruit juice are larger than those in Examples 3 and 4.

  In this example, first, a preform made of polyethylene terephthalate resin having a mass of 25 g is blow-molded to obtain a preformed bottle having an internal volume of about 500 ml, and then the preformed bottle is heated to shrink and blow-molded again. A heat-resistant pressure bottle with an internal capacity of 350 ml was manufactured as a base bottle by two-stage blow molding.

  Next, an amorphous carbon film having a thickness of about 50 nm was formed on the inner surface of the base bottle in exactly the same manner as in Example 3 except that the base bottle obtained in this example was used.

  As a result, the carbonated beverage containing fruit juice with a gas volume of 2.8 is filled by replacing the head space with carbon dioxide, and the center of the container is maintained at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes. Thus, a PET bottle for carbonated beverages having a volume increase rate of 4.0% after heat sterilization treatment was obtained. The PET bottle for carbonated beverages of this example has a smaller mass of the preform than that of Example 3, but the thickness of the entire bottle becomes more uniform and the crystallinity of the side walls becomes higher by the two-stage blow molding. It is considered that the volume increase rate is kept low because of the high rigidity of the body. The volume increase rate was measured in the same manner as in Example 1.

Next, except using the carbonated beverage PET bottle obtained in this example, exactly the same as in Example 3, the amount of carbon dioxide gas in the carbonated beverage containing fruit juice in the carbonated beverage PET bottle, The oxygen transmission rate of the carbonated beverage PET bottle was measured. The results are shown in Table 3.
[Comparative Example 6]
In this comparative example, the base bottle produced in Example 5 was filled with a carbonated beverage containing fruit juice with a gas volume of 2.8 without replacing any gas barrier coating, with the headspace replaced with carbon dioxide gas, for 35 minutes. A PET bottle for carbonated beverages having a volume increase rate of 4.2% after the heat sterilization treatment was performed so that the center of the container was kept at a temperature of 65 ° C. for 10 minutes or more by a hot water shower. The volume increase rate was measured in the same manner as in Example 1.

  Next, except for using the carbonated beverage PET bottle obtained in this Comparative Example, exactly the same as Example 3, the amount of carbon dioxide reduction in the carbonated beverage containing fruit juice in the carbonated beverage PET bottle, The oxygen transmission rate of the carbonated beverage PET bottle was measured. The results are shown in Table 3.

表３から、内面側にガスバリア被膜を備え、ガスボリューム２．８の果汁入り炭酸飲料を充填し、３５分間の熱水シャワーにより容器中心部が６５℃の温度に１０分間以上保持されるようにして加熱殺菌処理を行った後の体積増加率が８．０％以下である実施例５の炭酸飲料用ＰＥＴボトルによれば、前記充填から４週間後でも酸素透過量によって示される酸素バリア性が０．０１５ｍｌ／ボトル／日以下と良好であり、前記果汁入り炭酸飲料中の炭酸ガス減少量も少なく、前記果汁入り炭酸飲料を充填した後の殺菌処理等における室温より高温の環境下でも、優れたガスバリア性を保持していることが明らかである。

From Table 3, a gas barrier coating is provided on the inner surface side, filled with a carbonated beverage containing fruit juice with a gas volume of 2.8, and the center of the container is kept at a temperature of 65 ° C. for 10 minutes or more by hot water shower for 35 minutes. According to the PET bottle for carbonated beverages of Example 5 in which the volume increase rate after performing the heat sterilization treatment is 8.0% or less, the oxygen barrier property indicated by the oxygen permeation amount is 4 weeks after the filling. 0.015 ml / bottle / day or less is good, the amount of carbon dioxide in the fruit juice-containing carbonated drink is small, and excellent even in an environment at a temperature higher than room temperature in the sterilization treatment after filling the fruit juice-containing carbonated drink. It is clear that the gas barrier property is maintained.

  On the other hand, a carbonated beverage containing fruit juice with a gas volume of 2.8 was filled, and a heat sterilization treatment was performed so that the center of the container was kept at a temperature of 65 ° C. for 10 minutes or more by a hot water shower for 35 minutes. The PET bottle for carbonated drinks (Comparative Example 6) having a volume increase rate of 8.0% or less but not equipped with a gas barrier film is the oxygen permeation amount after 4 weeks from the filling, in the carbonated drink containing fruit juice. It is clear that the amount of carbon dioxide gas reduction is larger than that in Example 5.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory sectional drawing which shows one structural example of the CVD apparatus used for this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... CVD apparatus, 4 ... Processing chamber, 5 ... Microwave generator, 8 ... Exhaust chamber, 10 ... Base bottle, 19 ... Gas introduction pipe | tube.

Claims (6)

In a plastic bottle for carbonated drinks provided with a gas barrier coating formed by plasma CVD on the inner surface side,
A plastic bottle for carbonated drinks, wherein the volume increase rate in an environment higher than room temperature is 8.0% or less.   2. The carbonated beverage according to claim 1, wherein the volume increase rate in an environment higher than room temperature is a value after filling with carbonated water having a gas volume of 4.2 and storing at a temperature of 40 ° C. for 2 weeks. Plastic bottle.   The volume increase rate in an environment higher than the room temperature is a value after a heat treatment is performed in which carbonated water having a gas volume of 2.8 is filled and the center of the container is kept at a temperature of 65 ° C. for 10 minutes or more. The plastic bottle for carbonated drinks of Claim 1 characterized by these.   The carbon dioxide film according to any one of claims 1 to 3, wherein the gas barrier film is an amorphous carbon film whose main constituent element is carbon formed by plasma CVD from a starting material containing carbon atoms. Plastic bottle for beverages.   The gas barrier coating is a silicon oxide-containing coating in which the Si / O ratio formed by plasma CVD from a starting material containing an organosilicon compound is in the range of 1 / 1.5-1 to 1 / 2.2 in atomic ratio. The plastic bottle for carbonated drinks of any one of Claim 1 thru | or 3 characterized by these.   The plastic bottle for carbonated beverages according to any one of claims 1 to 5, wherein the plastic bottle is a polyester bottle.

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