JPH01213116A - Food packaging methods - Google Patents

Abstract

PURPOSE:To provide a packaged food, by laminating a gas-barrier layer and an adhesive layer on a resin foaming sheet, heating a container forming part of this laminate to form a container in such a manner that its outer surface is made up by the foaming sheet, filling the container with food, subjecting the same to gas replacing treatment and sealing the container opening with a lid sheet. CONSTITUTION:A food packaging sheet consists of a container forming sheet and a lid sheet, the former being a laminate with a gas-barrier layer 3 and an adhesive layer 4 formed on the surface of a resin foaming sheet 2 having an expansion rate of 1.1-20 and the latter being a laminate with a gas-barrier layer 7 and an adhesive layer 8 formed on a thermoplastic resin sheet 6. The container forming part of the sheet is heated to form a container-like bowl in such manner that the foaming part of the sheet makes up the outer surface thereof and this bowl is filled with food, followed by a gas replacing treatment. The lid sheet is thereafter placed on the opening edge of the container-like bowl to heat seal the adhesive layers of these two sheets. Each container thus formed is cut off from the sheets, resulting in an efficient food packaging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for filling and packaging food into containers formed from resin foam sheets such as polystyrene resins, polypropylene resins, and polypropylene resins.

[Prior art]

BACKGROUND ART Conventionally, containers made of resin foams such as polystyrene resins and polypropylene resins have been used as various food containers because they are easy to use due to their rigidity and have excellent surface aesthetics.

However, such resin foam does not have a gas barrier.
Due to its poor performance, it cannot be used as a container for preventing oxidative deterioration of foods by using gas replacement, etc.

On the other hand, thermoplastic resin films with high gas barrier properties such as nylon are heated and formed into a container shape.
After filling the container-shaped recess with food and displacing the gas, a similar gas barrier film is placed on the opening surface of the container-shaped recess, and the film is sealed by heat sealing. Methods for cutting and separating the package from the film are known. Such a packaging method has excellent productivity because it is carried out by automatic equipment and can produce a gas-substituted food package directly from a thermoplastic resin film. However, as described above, such packaging methods have not been applied to the production of packages using resin foam sheets.

〔the purpose〕

An object of the present invention is to provide a packaging method for obtaining a gas-substituted food package using a resin foam sheet.

〔composition〕

According to the invention, in the method of packaging food, (i)
Gas barrier layer and adhesive M on the surface of the resin foam sheet
(ii) heating the molding corresponding portion of a foam sheet for container molding having a laminated structure in that order; (iii) a step of filling the container-shaped recess of the foam sheet with food; (ilv) a step of replacing gas in the container-shaped recess of the foam filled with the food; (V) ) A structure in which a gas barrier layer and an adhesive layer are laminated in that order on the surface of a thermoplastic resin sheet on the opening surface of the gas-substituted food filling container-like recess, or a gas barrier layer on the surface of the outer thermoplastic resin sheet. A cover sheet having a structure in which adhesive layers are laminated is stacked so that the adhesive layer is in contact with the adhesive layer on the opening surface of the foam sheet, and heat-sealed to close the opening to the lid. (vi) from a foam sheet having a food-filled container-shaped recess whose opening is sealed with the lid sheet, the food-filled container-shaped recess is used as a food packaging body; There is provided a food packaging method characterized by comprising a step of cutting and separating.

In the present invention, two types of food packaging sheets are used in combination: a container forming sheet 1- and a lid sheet forming the container lid. In this case, the container forming sheet has a structure in which a gas barrier layer and an adhesive layer are laminated in that order on the surface of a resin foam sheet with an expansion ratio of 1.1 to 20 times, preferably 2 to 15 times. It is something. The container lid sheet has a structure in which a gas barrier layer and an adhesive layer are laminated on a thermoplastic resin sheet, or in which an adhesive layer is laminated on a thermoplastic resin film outside the gas barrier.

In the method of the present invention, first, a resin foam sheet (hereinafter simply referred to as a foam sheet) having a gas barrier layer and an adhesive layer on the surface forming the main body of the container is heated at a portion corresponding to molding. do. This heating temperature is
The thermoforming temperature of the foam sheet may be sufficient, usually 9.
It is in the range of 0 to 250°C.

Next, a container-shaped recess is formed in this heated foam sheet. This molding can be performed by vacuum molding, pressure molding, match molding, etc. using a metal mold. This molding is done so that the foam forms the outer surface of the foam sheet, and sometimes multiple moldings can be made. In this way, a sheet is obtained in which one or more container-shaped recesses are formed on the surface of the foam sheet.

Next, after filling the recesses of the foam sheet in which the container-shaped recesses have been formed with a desired food product, this is subjected to gas replacement treatment. This gas replacement can be carried out by a conventionally known method, for example, by once creating a vacuum in a sealed chamber and then introducing a required gas, such as nitrogen gas, carbon dioxide gas, or a mixture thereof.

By repeating this operation many times, gas replacement with an oxygen concentration of 1% or less can be achieved. After this gas replacement, in the same sealed room, the lid sheet 1- is placed on the open surface of the foam sheet having a container-shaped recess filled with food and whose internal gas has been replaced, and the two are heat-sealed. In this case, the heat fusion is performed by adhesive layer surfaces provided on each surface of the foam sheet and the lid sheet.

As described above, a sheet-like article is obtained in which the container-shaped concave portion of the foam sheet is filled with food, the internal gas is replaced, and the lid sheet is fused to the opening surface. Each container is cut and separated from this sheet-like material to obtain a food package.

As the material for the container-molding foam sheet used in the present invention, thermoplastic resins with high rigidity such as polystyrene resins and polypropylene resins are used.

The thickness of this resin foam sheet is usually 0.2 to 5 mm,
Preferably it is 0.5 to 2III++. In addition, the materials for the sword subarya layer formed on the surface include saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyvinylidene chloride, polyamide, polyester,
Metal salts, metal-deposited films, etc. are used. The thickness of the gas barrier layer is about 0.005 to 0.05 mm, preferably about 0.01 to 0.02 mm. Examples of the material for the adhesive layer include thermoplastic #1Iff such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ionomer.

The lid sheet used in the present invention usually has a structure in which a gas barrier layer and an adhesive Jm are laminated in this order on the surface of a profiteer resin sheet. In this case, as the base resin sheet, in addition to polyolefins such as polyethylene and polypropylene, general-purpose thermoplastic resins such as polyester and polyamide are used. The thickness of this base resin sheet is usually 0.03 to 5 mm, preferably 0.07 to 0.15 mm. As the materials for the gas barrier layer and the adhesive layer, those mentioned above are used. When a material with excellent gas barrier properties such as polyamide or polyester is used as the lid sheet, the gas barrier layer can be omitted.

In the container molding sheet 1- used in the present invention, an adhesive layer can be interposed between the gas barrier layer and the foam sheet or between the gas barrier layer and the adhesive layer, if necessary. Furthermore, a gloss-imparting film, a surface reinforcing film, etc. can be laminated on the outer surface of the container-forming sheet, and a coloring material or printing can be applied thereto.

In addition, in the lid sheet used in the present invention, an adhesive layer may be provided between the gas barrier layer and the base resin sheet 1- or between the gas barrier layer and the adhesive layer 1-, if necessary. can be done.

FIG. 1 shows an explanatory cross-sectional view of one example of a food package obtained by the present invention. In the figure, 1 indicates the main body of the container, which is composed of a laminate consisting of a resin foam layer 2, a gas barrier Jd3, and an adhesive layer 4. 5 indicates a container lid;
It is composed of an M-layer body consisting of a transparent resin layer 6, a gas barrier layer 7, and an adhesive N8. 9 is a filling gas space, 1
0 indicates food.

Preferred configuration examples of the container forming sheet and lid sheet 1 to 1 in the present invention are as follows.

(]) Configuration example of container molding sheet 1- (i) Resin foam sheet polystyrene resin, polypropylene resin, or functional resin.

(ji) Gas Barrano G Saponified ethylene-vinyl acetate copolymer (including partially saponified product), aromatic nylon resin or its co-condensed nylon, or vinylidene chloride resin or its chloride.

(iii) Surface adhesive layer low density polyethylene, linear low density polyethylene or ethylene-vinyl acetate copolymer.

(iv) Adhesive J between the foam and the gas barrier 1
FI (a) one or more resins selected from low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate copolymers, (b) terpene resin, and/or (c) petroleum resin or its hydride. (d) Compositions consisting of low melting point polyolefins such as paraffin and crystalline wax.

(2) Example of structure of lid sheet (i) Base resin low density polyethylene, ethylene-vinyl acetate copolymer or linear low density polyethylene (ii) Gas barrier layer Gas barrier layer of the container molding foam sheet Same as shown for.

(iii) Surface adhesive layer Mainly composed of one or more selected from low-density polyethylene, ethylene-vinyl acetate copolymer, and linear low-density polyethylene, and optionally one of terpenes, petroleum resin, and paraffin. A combination of.

The method of the present invention can be carried out using a variety of equipment, for example, a MULTIVAC R700
0 (MULTIVACEExport AG).

[Effects] According to the present invention, food can be efficiently packaged in a resin foam sheet container in a gas-substituted state. In this case, the foods include processed meat products such as ham and sausages, and foods that are susceptible to quality deterioration due to oxygen, such as fresh seafood.

Since the food package obtained by the present invention is filled in a rigid resin foam sheet container, it is convenient to handle, has a beautiful appearance, and has high commercial value. Furthermore, the inside of the package is replaced with gas, and the sheets constituting the container and lid have excellent gas barrier properties, which prevents oxygen from entering from the outside, reducing the quality of the food inside. Deterioration is prevented.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of one example of a food package obtained by the present invention. DESCRIPTION OF SYMBOLS 1... Container main body, 2... Resin foam layer, 3... Gas barrier layer, 4... Adhesive layer, End... Container lid, 6...
Transparent resin layer, 7... Gas barrier layer, 8... Adhesive layer, 9... Filled gas space, 10... Food. Applicant's agent Patent attorney Toshiaki Ikeura (and 1 other person) -12=

Claims (1)

[Claims] (1) In a method for packaging food, (i) heating a moldable portion of a foam sheet for container molding having a structure in which a gas barrier layer and an adhesive layer are laminated in that order on the surface of a resin foam sheet; (ii) forming a container-shaped recess in the heated foam sheet so that the outer surface is made of the foam sheet; (iii) filling the container-shaped recess of the foam sheet with food; (iv) replacing the inside of the container-shaped recess of the foam filled with the food with gas; (v) displacing gas on the surface of the thermoplastic resin sheet on the opening surface of the gas-replaced food-filled container-shaped recess; The lid sheet has a structure in which a barrier layer and an adhesive layer are laminated in that order, or an adhesive layer is laminated on the surface of a gas barrier thermoplastic resin sheet, and the adhesive layer is on the opening surface. (vi) sealing the opening with the lid sheet by stacking the foam sheets in contact with the adhesive layer and heat sealing; (vi) sealing the opening with the lid sheet; 1. A food packaging method comprising the step of cutting and separating the food-filled container-like recesses as a food package from a foam sheet having the food-filled container-like recesses.