JP2012246000A - Plastic container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-walled plastic container having an excellent barrier property.SOLUTION: The plastic container 1 has a multilayered structure including an intermediate layer made of a gass-barrier resin, and inner and outer layers made of a humidity-resistant resin. A barrel part 5 of the plastic container 1 is formed in a thinner wall than other sections constituting the container, and its outer circumferential surface is covered with a gas barrier property film 8. A resin having the barrier property such as an ethylene-vinyl alcohol copolymer resin (EVOH), a nylon resin, or a cyclic olefin, may be used for the gass-barrier resin of the intermediate layer. An olefin resin such as polypropylene (PP) or polyethylene (PE) is favorably used for the humidity-resistant resin of the inner layer and the outer layer 4.

Description

  The present invention relates to a plastic container having excellent barrier properties.

  Conventionally, as a plastic container having a barrier layer, a container having a multilayer structure in which an olefin resin is disposed in an inner layer and an outer layer and an ethylene-vinyl alcohol copolymer (EVOH) is disposed as an intermediate layer is known. This multi-layer plastic container with olefin resin in the inner and outer layers has high moisture resistance, is relatively soft and has excellent moldability, so it can be easily blow-molded into the required shape, and is a container for various foods, beverages or chemicals It is used as.

As a container having improved barrier properties, for example, cited document 1 discloses a plastic container in which a gas barrier thin film made of an inorganic thin film is provided on the entire surface of the container body. Reference 2 discloses a cup having a high barrier property in which a film having a high barrier property in which a thin film layer of an inorganic compound is provided on a plastic film.
Japanese Patent No. 4448241 Japanese Patent No. 3690089

  By the way, in recent years, for the main purpose of reducing the burden on the environment and reducing the cost, the amount of plastic used is reduced to make it thinner and lighter. However, there is a problem that various physical properties of the container itself, including the barrier property, are reduced as the thickness is reduced.

  Then, an object of this invention is to provide the thin plastic container excellent in barrier property.

  In the plastic container of the present invention, as described in claim 1, the body portion is formed thinner than other portions constituting the container, and the outer peripheral surface of the body portion is covered with a gas barrier film. It is characterized by.

  According to the present invention, it is possible to obtain a plastic container which is excellent in barrier properties, thin and lightweight.

  Further, by adopting a multi-layer structure and disposing a gas barrier resin in the intermediate layer, even if a defect portion is generated in the gas barrier film, it can be compensated for, and stable barrier performance can be provided.

  The plastic container 1 according to the present invention is blow molded, and is mainly used as a cosmetic and medical container. The plastic container 1 has a multilayer structure including an intermediate layer 2 made of a gas barrier resin, and an inner layer 3 and an outer layer 4 made of a moisture resistant resin. As the gas barrier resin of the mid layer 2, a resin having a barrier property such as ethylene-vinyl alcohol copolymer resin (EVOH), nylon resin, cyclic olefin can be used. As the moisture resistant resin for the inner layer 3 and the outer layer 4, an olefin resin such as polypropylene (PP) or polyethylene (PE) is preferably used.

  The plastic container 1 is thin as a whole, and its body part 5 is formed to be thinner than other parts constituting the container. That is, the body part 5 is formed thinner than the shoulder part 6 and the bottom part 7 connected to the body part 5, and the shoulder part 6 and the bottom part 7 are relatively thicker than the body part 5. Here, the trunk | drum 5 is located in the center part of a container, and is a part on the boundary where the curvature changes, The upper part is the shoulder part 6, and the lower part is the bottom part 7. A gas barrier film 8 is tightly wound around the entire outer peripheral surface of the body portion 5. The gas barrier film 8 can be attached by using a known pressure-sensitive adhesive on the inner surface side in contact with the container after the above blow molding. In blow molding, it is also possible to insert mold by placing on the mold cavity surface. Due to the covering effect of the gas barrier film 8, the body 5 can maintain high barrier properties even if it is thin. Further, the shoulder portion 6 and the bottom portion 7 which are difficult to be attached without wrinkles of the film are made thick so that the entire barrier property is maintained. In addition, if the thickness of the shoulder part 6 or the bottom part 7 is blow molding, for example, it can be made thick by controlling the thickness of a parison at the time of parison extrusion. In addition, it is preferable that the trunk | drum 5 is a shape where it is easy to adhere | attach the gas barrier film 8 over the whole (it is a cylindrical shape in the example of illustration). With this configuration, a plastic container that is as thin as possible, lightweight, and has high barrier properties can be obtained. The present invention is not limited to a multi-layer container, and may be a single-layer container. In that case, the shoulder 6 and the bottom 7 are thicker than the body 5, and the body 5 It is preferable that the thickness of the thinnest portion of the shoulder portion 6 and the bottom portion 7 is 1.3 times or more with respect to the maximum thickness in order to maintain high barrier properties.

  The gas barrier film 8 is a film having a barrier property, and when oxygen barrier property is required, a film made of nylon, ethylene-ethylene vinyl alcohol copolymer, polyvinylidene chloride, polyester, or the like is used. When a barrier is required, a film made of stretched polypyropylene, high density polyethylene, polyvinylidene chloride, or the like may be used. If both an oxygen barrier and a water vapor barrier are required, use a stretched nylon, stretched polypropylene, or stretched polyester film coated with polyvinylidene chloride in combination with the aforementioned films. That's fine. In addition to the plastic film, a film in which a thin film layer of an inorganic compound such as silicon oxide, aluminum oxide, or magnesium oxide is provided on the plastic film can also be used. Among these, the use of a film in which aluminum oxide is thinly deposited on a thin film is preferable because the barrier property is very high and the transparency is not impaired. The gas barrier film 8 may not be an aluminum vapor-deposited film as long as it has excellent gas barrier properties, but an aluminum vapor-deposited film is most suitable because it has excellent moisture resistance as well as gas barrier properties. Further, the gas barrier film 8 can be displayed as required by using a part or all of the gas barrier film 8 as a display label. Reference numeral 9 denotes a mouth portion which is thicker than other portions connected to the shoulder portion 6.

  In the gas barrier film 8, the occurrence of pinhole-like gas barrier defects such as folds and wrinkles due to deformation strain is unavoidable, but a resin having gas barrier properties is sandwiched with other resins as the intermediate layer 2 of the body portion 5. Since it arrange | positions in the state, the defect | deletion part of the gas barrier film 8 can be supplemented, and the stable gas barrier property can always be hold | maintained.

  Furthermore, when the gas barrier film 8 is excellent in moisture resistance such as an aluminum vapor deposition film, the gas barrier resin constituting the intermediate layer 2 can maintain high gas barrier properties without being affected by water vapor from the outside. Therefore, it is possible to further reduce the thickness of the plastic container 1 without impairing the gas barrier property.

It is sectional drawing which shows one Embodiment of the plastic container which concerns on this invention. 1 is an overall perspective view of a plastic container according to the present invention. It is a partially expanded sectional view of the plastic container shown in FIG.

DESCRIPTION OF SYMBOLS 1 Plastic container 2 Middle layer 3 Inner layer 4 Outer layer 5 Trunk part 6 Shoulder part 7 Bottom part 8 Gas barrier film 9 Mouth part

Claims (4)

The trunk is formed thinner than other parts that make up the container,
A plastic container, wherein the outer peripheral surface of the body is covered with a gas barrier film.   The plastic container according to claim 1, wherein the minimum thickness of the other portion is 1.3 times or more of the maximum thickness of the body portion.   3. The plastic container according to claim 1, further comprising an intermediate layer made of a gas barrier resin, and an inner layer and an outer layer made of a moisture resistant resin.   The plastic container according to any one of claims 1 to 3, wherein the gas barrier film is a film on which aluminum oxide is deposited.

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