JP2005329951A - Gas permeation valve and container equipped with the gas permeation valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas permeable valve which allows a package requiring gas barrier property to prevent its burst or deformation caused by a change in inner pressure before being unsealed and maintain initial safety and designedness for a long time, and to provide a container having the gas permeable valve. <P>SOLUTION: The gas permeable valve is formed on a spout of the container or on a part of the spout, and has a diaphragm closing the spout. An inorganic oxide thin film having gas barrier property, such as silicon oxide, is formed on some part of the surface of the diaphragm, and can be projected outwardly or inwardly in reverse of the container in response to a change in the inner pressure of the container. The inorganic oxide thin film is distorted as it is reversed in shape, which changes the gas barrier property of the film to make gas permeable. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a gas permeation valve made of a diaphragm capable of preventing rupture and deformation associated with a change in internal pressure of a package, and maintaining safety and design characteristics in an initial state for a long period of time, and the gas permeation valve. Concerning the container.

  While food packaging is required to have a function of blocking oxygen, it responds to increased internal pressure by discharging carbon dioxide gas, like freshly roasted coffee beans and sake that does not stop fermentation. There is a need to. In this case, there is a risk of bursting in severe cases. In addition, in the contents containing an enzyme that takes in oxygen in the head space and generates oxide, the oxygen in the head space is consumed, and the internal pressure of the package becomes lower than the atmospheric pressure, and particularly in a plastic container, the body part is deformed. It will be. As described above, the package has a face that the barrier property must be lowered to prevent deformation.

  Various measures have been taken to solve these problems, but all have various problems and have not been completely solved. For example, a pressure-regulating valve used for roasted coffee beans is not optimal for maintaining freshness because the air flows back easily.

  In recent years, a technique for coating a plastic thin film with a ceramic has been known. Most of these films are formed on a base material made of a single material to improve barrier properties. Recently, not only films but also container-shaped structures can be formed. became. By using this technology, it has become possible to realize a packaging material that can change the gas barrier property of the container during use at low cost and without breaking the packaging material.

  When a product that normally requires gas barrier properties causes deformation or rupture due to an increase or decrease in internal pressure, it is necessary to adjust the pressure inside the container while minimizing a decrease in gas barrier properties. In the adjustment, it is required not to make the internal pressure completely equal to the atmospheric pressure, but to prevent deformation while suppressing the reaction inside the container. Therefore, when the gas pressure is adjusted by mechanically opening and closing the seal portion, a large amount of air is drawn back, which hinders subsequent contents protection. Moreover, there are many types of pressure adjusting mechanisms used as food packaging materials that break the package.

The patent literature is described below.
JP-A-6-329179 For example, in Japanese Patent Application Laid-Open No. 2001-354276, in order to prevent the bursting of a package heated in a microwave oven and having an increased internal pressure, another film is bonded to the outside of the film that has been previously perforated. A structure has been proposed in which the seal peels off when the internal pressure is reached. These are proposals for destroying the package immediately before taking out the contents, and this method cannot be used as it is for a gas venting method during long-term storage.

When a package that requires gas barrier properties needs to be prevented from being ruptured or deformed before opening, there is a need for a method that can provide appropriate gas permeability without destroying the package.

  In order to solve the above-mentioned problems, the present invention prevents a package that requires gas barrier properties from bursting or deforming before being opened due to a change in the internal pressure of the package, and can maintain safety and design characteristics in an initial state. An object of the present invention is to provide a gas permeation valve that can be maintained for a period of time and a container equipped with the gas permeation valve.

To achieve the above objectives, ie
The invention according to claim 1 has a diaphragm that is provided in a container outlet portion or a part thereof and closes the outlet portion, and a gas barrier inorganic oxide such as silicon oxide is provided on any surface of the diaphragm. A thin film is formed, and can be inverted in a convex shape from the outside of the container to the inside of the container according to changes in the internal pressure of the container. It is a gas permeation valve characterized by becoming possible.

  The invention according to claim 2 is the gas permeation valve according to claim 1, wherein the diaphragm is made of a plastic sheet.

  The invention according to claim 3 is the gas permeation valve according to claim 2, wherein the plastic sheet has a thickness in the range of 0.2 to 0.3 mm.

  The invention according to claim 4 is the gas permeation valve according to any one of claims 1 to 3, wherein the diaphragm is molded by vacuum molding or injection molding.

  An invention according to claim 5 is a container comprising the gas permeation valve according to any one of claims 1 to 4.

  A package that requires gas barrier properties can be prevented from rupturing or deforming before opening due to changes in the internal pressure of the package, and the design can be maintained for a long time in its initial state by eliminating safety and appearance defects due to deformation. It has become possible to provide a gas permeation valve that can be used and a container equipped with the gas permeation valve.

  Moreover, if the package pressure when the diaphragm of the gas permeation valve is reversed matches the pressure of the gas released while the contents deteriorate, the gas permeation valve may function as an indicator for indicating the expiration date. Is possible.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an exemplary embodiment of the invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a container provided with a gas permeation valve made of the diaphragm of the present invention. FIG. 2 is an explanatory view of the container equipped with the gas permeation valve made of the diaphragm shown in FIG. FIG. 3 is an explanatory view of the container equipped with the gas permeation valve made of the diaphragm shown in FIG. 1, in which the inner pressure of the container is lowered, the diaphragm is inverted in a convex shape inside the container, and gas can be transmitted. .

As shown in FIG. 1 (a), a container 10 provided with a gas permeation valve as an embodiment of the present invention is provided with a gas permeation valve comprising a diaphragm 14 that closes a spout 13 of a container body 11. It is a bottle container formed integrally. And the gas permeation valve which consists of the diaphragm 14 is a container inner surface side of the plastic sheet base material 14a, as shown in FIG.1 (b) by expanding the cross section of a part (A) of the diaphragm 14 shown in FIG. Is formed with a gas barrier inorganic oxide thin film 14b such as silicon oxide, and can be inverted in a convex shape outside or inside the container in accordance with a change in the internal pressure of the container. The gas barrier property of the physical thin film is changed to enable gas permeation.

  As shown in FIG. 2, in the container 20 having the gas permeation valve composed of the diaphragm 24 of the present invention, the container internal pressure p rises, the diaphragm 24 is inverted in a convex shape to the outside of the container, and the container of the diaphragm 24 The gas barrier inorganic oxide thin film such as silicon oxide provided on the inner surface side is cracked in the gas barrier inorganic oxide thin film due to the strain at the time of reversal, and the gas barrier property is changed to enable gas permeation. It is.

  Further, as shown in FIG. 3, in the container 30 having the gas permeation valve composed of the diaphragm 34 as one embodiment of the present invention, the container internal pressure p is lowered, and the diaphragm 34 is inverted in a convex shape inside the container. However, the gas barrier inorganic oxide thin film such as silicon oxide provided on the inner surface of the diaphragm of the diaphragm causes a crack or the like in the gas barrier inorganic oxide thin film due to the strain at the time of reversal, and the gas barrier property is changed to change the gas It can be transmitted.

  In the container provided with the gas permeation valve made of the diaphragm of the present invention, the gas barrier inorganic oxide thin film is inverted in a convex shape to the outside or the inside of the container in accordance with the change in the container internal pressure as described above. By changing the gas barrier property to allow gas permeation, packages that require gas barrier property can be prevented from bursting or deforming before opening due to changes in the internal pressure of the package, eliminating safety and poor appearance due to deformation. Thus, the design property can be maintained for a long time in the initial state. Moreover, if the package pressure when the diaphragm of the gas permeation valve is reversed matches the pressure of the gas released while the contents deteriorate, the gas permeation valve may function as an indicator for indicating the expiration date. Is possible.

  As described above, the gas permeation valve of the present invention has a gas barrier property when the content of a container having a gas permeation valve made of a diaphragm having a gas barrier inorganic oxide thin film changes its internal pressure as compared with the atmospheric pressure due to reaction. The purpose is to cause distortion in a part of the inorganic oxide thin film to lower the barrier property. In the process of forming the gas barrier inorganic oxide thin film on the plastic sheet substrate constituting the diaphragm, the adhesion strength at the interface between the substrate and the thin film can be controlled by the formulation. Therefore, a gas barrier property can be obtained, but by making the formulation weak against a large strain, the gas permeability increases due to the strain due to the deformation of the package. And by setting it as the diaphragm structure which is displaced greatly instantly by a pressure difference so that the distortion by deformation | transformation becomes large, the gas barrier property in the part will fall reliably. In this case, the reduced gas permeability value is intermediate between the gas permeability of the substrate and the gas permeability of the gas barrier inorganic oxide thin film, and the subsequent content storage performance and pressure adjustment speed are taken into consideration. Designed.

  Examples of the container provided with the gas permeation valve of the present invention include various types of containers such as a bag, a cup, and a bottle. The gas permeation valve of the present invention can be attached to a bag-made film and used, and in that case, for example, it is optimal as a bag for wrapping contents against an increase in internal pressure by releasing carbon dioxide such as coffee beans. . Further, the same processing is possible for a paper container laminated with a resin, and when used for a cup-shaped container, a gas permeation valve can be attached to a soft packaging material used for a lid.

  Further, in the case of a bottle in which the gas permeation valve of the present invention is integrally formed with the container body, it is possible to cope with any content in which the container internal pressure rises or falls. The gas permeation valve of the present invention is molded by vacuum molding or injection molding.

As a method for forming a gas barrier inorganic oxide thin film on a plastic sheet base material constituting the diaphragm, an inorganic oxide thin film such as silicon oxide by plasma CVD is useful. With this method, the adhesion strength with the substrate interface can be adjusted by the deposition gas formulation, etc., and the gas permeability can be adjusted along with the deformation of the diaphragm by changing the followability to the film distortion. It is.

  The inorganic oxide thin film such as silicon oxide on the plastic sheet base material constituting the diaphragm may be provided on either the inner surface side or the outer surface side of the container. In addition, when preventing the vacuum deformation of the container, a gas barrier inorganic oxide thin film such as silicon oxide can be formed on the entire surface of the container in the case where there is a concern that the contents may deteriorate due to consumption of oxygen.

  As a source gas that can be used for forming a silicon oxide thin film by plasma CVD, hexamethyldisiloxane (HMDSO) or trimethylsiloxane can be used as the main gas. This makes it possible to form a silicon oxide thin film. In addition to oxygen, ozone, carbon dioxide, or the like can be used as the reactive gas.

  Specific examples of the present invention will be described below.

  A 30 g high-density polyethylene hollow container with a full water volume of 550 ml was molded, which was made of an outer convex diaphragm whose part could be reversed by a pressure difference between the front and back sides. The thickness of the diaphragm portion was set to 0.2 to 0.3 mm. A silicon oxide film was applied to the inner surface of the diaphragm portion, and 500 ml of enzyme-containing bath agent was filled. Two weeks later, the diaphragm was reversed inside, and no change was observed in the container appearance after one month.

  A 0.2 mm thick polyester sheet was processed by vacuum forming a diaphragm that initially protrudes inward and reverses outward when an internal pressure of 0.02 Pa is applied. The inner surface was coated with a silicon oxide film, welded to a film made of an outer polyester layer having a gas barrier property, formed into a bag having a length of 140 mm and a width of 100 mm, and filled with 50 g of coffee beans immediately after roasting. After 1 week, the packaging swelled and the diaphragm was inverted, but the state was kept almost unchanged until 3 weeks later. No bag breakage was seen.

  As a comparative example of the present invention, the container excluding the diaphragm in Example 1 was filled with 500 ml of enzyme-containing bath agent without a silicon oxide film. Two weeks later, the container body was greatly deformed inward.

  As a comparative example of the present invention, the film used in Example 1 was made into the same size and filled with 50 g of coffee beans immediately after roasting. After 10 days, the package burst with internal pressure.

  Each of the containers equipped with the gas permeation valve made of the diaphragm of the present invention obtained in Examples 1 and 2 described above is designed to prevent rupture and deformation, and to eliminate the appearance defects due to safety and deformation. It was possible to maintain the initial state for a long time.

It is sectional drawing which shows an example of the container provided with the gas permeation valve which consists of a diaphragm of this invention. In the container provided with the gas permeation valve which consists of a diaphragm shown in FIG. 1, the container internal pressure rises, and the diaphragm reverses in a convex shape to the outside of the container so that the gas can be transmitted. In the container provided with the gas permeation valve which consists of a diaphragm shown in FIG. 1, the container internal pressure falls, The diaphragm reverses in the convex shape inside the container, and it is explanatory drawing which can permeate | transmit gas.

Explanation of symbols

10, 20, 30... Container 11 having a gas permeation valve made of a diaphragm 11... Container body 12... Container skirt 13 ... Spout 14, 24, 34. Permeation valve 14a ... Plastic sheet base material layer 14b constituting diaphragm ... Gas barrier inorganic oxide thin film layer p ... Container internal pressure

Claims (5)

  A diaphragm provided in a container outlet portion or a part thereof and closing the outlet portion, and a gas barrier inorganic oxide thin film such as silicon oxide is formed on any surface of the diaphragm; According to a change in internal pressure, the gas barrier property of the gas barrier inorganic oxide thin film can be changed so that the gas can permeate by changing the gas barrier property of the gas barrier inorganic oxide thin film by the strain at the time of the reverse. Gas permeation valve.   The gas permeation valve according to claim 1, wherein the diaphragm is made of a plastic sheet.   The gas permeation valve according to claim 2, wherein a thickness of the plastic sheet is in a range of 0.2 to 0.3 mm.   The gas permeable valve according to any one of claims 1 to 3, wherein the diaphragm is molded by vacuum molding or injection molding.   A container comprising the gas permeation valve according to any one of claims 1 to 4.

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