JPS627065B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention has a pre-formed food storage part, a peripheral part of the storage part, and after storing food in the content part,
The present invention relates to a food container in which a lid material is thermally bonded to the peripheral portion and hermetically packaged. [Prior Art and its Problems] In recent years, containers made of plastic sheets and provided with a housing part having a sealing peripheral part have been used for processed meat products and other products, as shown in Japanese Patent Laid-Open No. 48-65092, for example. It has been widely used in fish paste products, processed agricultural products, confectionery, etc. However, in many of these containers, the periphery around the accommodating portion is curled, which significantly reduces the value of the product on store shelves. Immediately after vacuum forming these containers using a forming and packaging machine, there is almost no warpage. However, when the lid material was thermally bonded to the periphery after filling the storage portion with food, warping was noticeable even after bonding. In addition, in order to preserve food for a long time, when a container containing food and a lid that is heat-bonded is subjected to hydrothermal bacterium at 75 to 95 degrees Celsius for 10 to 30 minutes, the periphery of the container will warp significantly. . For example, a plastic sheet as shown in FIGS. 1A and 1B is molded, and the contents 1 are placed in the housing part 2 of a container body 6, which has a peripheral part 3 having a display part 4 in a part thereof, and a thermoformed housing part 2. There are three methods for vacuum packaging and sealing with the lid material 5. (b) After vacuum packaging the contents in the container body, the storage part and 2
Provide a ~3mm clearance and place the lid material around the periphery.
A method of heat bonding by pressing the seal side of the display section with a heat sealing machine. (b) A method in which the contents are vacuum-packed in a container, passed through a high-temperature chamber, and the temperature inside the chamber heat-bonds the lid material to the periphery, the seal side of the display. (c) A method of vacuum packaging the contents of the container and then heat-bonding the lid material to the periphery and seal side of the display section by contacting a heated heat sealing plate from the lid material side in a vacuum chamber. When thermal bonding is carried out by the above method, as mentioned above, the warpage in the peripheral areas, especially the corners, increases, resulting in a decrease in the in-store effect and commercial value. [Problem to be solved] Even if the container is made from a plastic sheet, the contents are vacuum-packed in the storage area of the container body with a peripheral area and a storage area, and the container is heat-bonded with a lid, the peripheral area will not warp. The objective is to obtain a food container with less waste. Another object of the present invention is to obtain a food container whose peripheral portion is less warped even when sterilized by boiling with hot water at 75 to 95°C. [Means for solving the problem] Molding a plastic sheet made of unstretched polypropylene/nylon/thermal adhesive resin with corona discharge treatment on both sides and a coating agent made of isocyanate-based anchoring agent and nitrified cotton applied to the outer surface. However, this problem can be solved by using a container body with a peripheral part and a storage part, and a lid material made of unstretched polypropylene/cellophane/thermal adhesive resin that has been treated with corona discharge and coated with the same coating agent on the outer surface as described above. did. [Function] The same unstretched polypropylene film is used for the outer layer of the container body and lid material, and the outer surface is coated with a coating agent, so it can be automatically heat-bonded using a heat sealing machine, and the polypropylene film will not whiten. do not have. Further, there is almost no warping of the peripheral portion during heat bonding or boil sterilization. [Example] An example will be described using drawings. As shown in FIG. 2, the food container is made up of a container main body 6 having a housing part 2 and a peripheral part 3, and a lid 5, and the peripheral part 3 of the container main body 6 and the lid 5 are thermally bonded. First, the lid material 5 is made of unstretched polypropylene film (20~40μ)/cellophane (#300~
Consists of three layers: #500)/thermal adhesive resin layer (40-80μ). The container body 6 is made of unstretched polypropylene film (30 to 70μ)/
Consists of three layers: nylon film (#30~#80)/thermal adhesive resin layer (50~100μ). Here, the cellophane used in the lid material may be any of cellophane coated on both sides with vinylidene chloride resin, moisture-proof cellophane, or ordinary cellophane. The heat-adhesive resin layer of the lid and the container body is made of polyethylene polypropylene, a mixed resin of polyethylene and ethylene-vinyl acetate copolymer, or an ionomer resin. The mixed resin of the heat-adhesive resin layer preferably has an ethylene-vinyl acetate copolymer content of 3 to 10% by weight. Each layer of the lid material is laminated using a urethane adhesive, and each layer of the container body is laminated using a polyester adhesive. Specific example 1

[Table] These materials are bonded with adhesive. Here, the lid material was bonded with a urethane adhesive, and the container body was bonded with a polyester adhesive. Using the above materials, a container body is formed using an Omori Kikai FV601N deep drawing packaging machine, and after filling the container with 150g of sliced pressed ham, it is covered with a lid material and vacuum packed at 160-170℃ for 11 seconds per minute. After shot sealing, the lid material side is heated to 160-170℃ using an infrared heater.
The lid material and the periphery of the container body were heat-bonded to obtain a container. This container was subjected to hot water sterilization treatment at 85°C for 20 minutes. Almost no warpage was observed in the food containers of the present invention. Specific example 2 Lid material: Polypropylene film (manufactured by Toray)
#3401) (20μ) External coating agent is the same KN cellophane as in Example 1 #300 Thermal adhesive resin layer: Surlyn #1707 DuPont (60μ) Container body: Polypropylene film (Toray)
#3401) (50μ) Intermediate layer: Vinylidene chloride resin coated nylon film #40 (manufactured by Toyo Gosei) Thermal adhesive resin layer: Same material as the lid material (80μ) Here, the lid material is made of urethane adhesive, and the container body is made of urethane adhesive. The layers were bonded together using a polyester adhesive. 130g of sliced roast ham was placed in a container body made of this material, vacuum-packed using the same packaging machine as in Example 1, sealed 10 times per minute at 150-160°C, and sealed from the lid side heated to 150-160°C. A portion corresponding to the periphery was heat-bonded using a disk to obtain a container. Almost no warpage was observed in this container. [Effect] Since the food container of the present invention has the above-described structure, even if the periphery of the container body and the lid are heat-bonded after vacuum packaging the contents, almost no warping occurs in the periphery. In addition, each polypropylene does not whiten, has an excellent appearance, and has an excellent in-store display effect. In addition, even when sterilized by boiling, there is almost no warping of the peripheral parts, making sterilization by boiling possible and long-term storage of the contents.

[Brief explanation of the drawing]

FIG. 1A is a plan view of the shape of the container of the invention, FIG. 1B is a side view of the shape of the container of the invention, and FIG. 2 is a sectional view of the container of the invention. 1...Contents, 2...Accommodating section, 3...Periphery,
4...display section, 5...lid material, 6...container body.

Claims (1)

[Claims] 1. Molding a plastic sheet in which unstretched polypropylene/nylon/thermal adhesive resin layers, both sides of which have been subjected to corona discharge treatment and coated with an isocyanate-based anchoring agent and a nitrified cotton coating agent, are laminated with a polyester adhesive. It consists of a container body with a peripheral part and a storage part, and a lid material made of a material in which unstretched polypropylene/cellophane/thermal adhesive resin layers, which have undergone the same treatment as the unstretched polypropylene of the container main body, are laminated with a urethane adhesive. ,
A food container formed by heat-bonding the peripheral part of the container body and a lid material after the contents are stored in the storage part of the container body.