JPH0680162A - Covering material for gas packed packaging - Google Patents

Abstract

PURPOSE:To provide a covering material for gas packed packaging to be used in a package filled with inert gas or the like. CONSTITUTION:A barrier film in low barrier efficiency is stuck to a barrier layer so that it can be peeled off, and thereby a covering material for gas packed packaging is made up. With such covering material, period for preservation of raw meat can be extended. As the barrier layer placed for lining the external layer can be peeled off without fail at a retail shop on the day of sale, dressed meat in fresh color can be presented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid member for packaging a gas pack used for a package body filled with an inert gas or the like.

[0002]

2. Description of the Related Art In order to stimulate demand of buyers, packaging at supermarkets is becoming more colorful, and buyers also tend to purchase fresh and good-looking products. For example, in the case of meat, the vivid red meat that is fresh and appetizing sells well, so generally trays made of expanded styrene, polyvinyl chloride, polystyrene, polypropylene, etc. are filled with raw meat, and then stretched with stretch film or the like. It is stretch wrapped. However, in this packaging form, there is a problem that it does not last long and that it takes time and labor in the backyard of a retail store such as a supermarket to wrap it on the same day.

Therefore, in order to give the reddishness of raw meat, the concentration of oxygen is increased and myoglobin in the meat is combined with excess oxygen to emphasize the red color. However, since oxygen is present excessively in this method, oxidation or spoilage is caused. Since there is a tendency to promote the deterioration of meat by the propagation of bacteria, some packagings that have been devised such as mixing carbon dioxide, which has an antibacterial effect, are in circulation.

[0004]

[Problems to be solved] However, in the conventional packaging body, the shelf life of meat is not so long in spite of the bacteriostatic effect of carbon dioxide because it is deteriorated by oxygen, and it has only one week. There is. Therefore, until the storefront is filled with an inert gas or the like, deterioration does not proceed, and oxygen or air may be injected into the storefront just before the display to start the reaction with myoglobin, but oxygen is injected again. Or, there is a problem in terms of equipment and manpower in repacking.

[0005]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems by devising a lid material, and a lid for a gas pack which is formed by releasably bonding a low barrier film and a barrier layer. It is a material.

When meat is placed on a packaging tray, filled with an inert gas such as nitrogen or carbon dioxide, and heat-sealed using the lid material for packaging a gas pack of the present invention, the barrier layer prevents the inert gas from remaining for a long time. It is retained, and the deterioration of meat is suppressed by its antioxidant action and bacteriostatic effect, and it becomes possible to deliver fresh contents to supermarkets and the like or store them for a long time.

In the supermarket, if the barrier layer of the lid material is peeled off immediately before the display, the low barrier film layer remains, so that oxygen in the atmosphere permeates the low barrier film layer and enters the inside while maintaining hygiene. , It is combined with myoglobin to generate redness of meat and stimulate consumers' willingness to purchase.

The low barrier film is made of a low density polyethylene, a linear low density polyethylene, an ethylene vinyl acetate copolymer, a polyolefin resin such as polypropylene, or a resin having a large gas permeability such as soft polyvinyl chloride or polystyrene. It is possible to use a thin film having a thickness of 10 to 100 μm.

Further, as the low barrier film, a so-called stretch film made of the above-mentioned resin or ultra-low density polyethylene, which has a composition for imparting elongation and tackiness, is used. The anti-fog property can be used as it is, and there is an effect that it can be displayed side by side with a conventional stretch wrapping body without causing any discomfort.

Further, when a perforated film is used as the low barrier film, there is an effect that the material can be relatively freely selected regardless of its gas permeability. The hole diameter of the perforated film is 0.01 mm to 1 mm (preferably 0.1 mm).
If it is 0.6 mm), oxygen can invade, but dust and insects cannot invade, which is hygienic. Moreover, since the holes are scattered on the film surface, the contents are not obscured.

This perforated film is perforated with a laser beam or a hot needle. As the material, besides the above, heat-sealable polyester, saponified ethylene vinyl acetate copolymer, biaxially stretched polyethylene terephthalate film and the like can be used. Can be used. It is also possible to use a multi-layer film having these resins on the side to be bonded to the barrier layer.

The oxygen permeability of these low barrier films is
Although it depends on the headspace of the gas pack package used and the like, it is generally preferable that the oxygen concentration in the gas pack package is 10 vol% or more within 24 hours, and the oxygen permeability is 1000 cc / m2 · 24h · atm · 25μ.・
Those having a temperature of 23 ° C. or higher can be preferably used.

As the barrier layer, a film having an oxygen barrier property can be generally used, and examples thereof include nylon, saponified ethylene vinyl acetate copolymer, polyvinyl alcohol,
Examples thereof include polyvinylidene chloride, metal foil, metal vapor deposition film and the like. The barrier film may be used as a single film, or may be a multi-layer film. Moreover, the thickness is not particularly limited.

An outer layer may be laminated on the outer side of the barrier layer, and the outer layer reinforces the barrier layer by backing it so as not to stretch or break when peeling the barrier layer from the low barrier film, thereby ensuring peeling. The biaxially stretched polyethylene terephthalate film is particularly preferable as long as it can withstand heating during heat sealing.

There are two methods for laminating the barrier film, one is a method in which at least one surface of the film is subjected to corona treatment and immediately thermocompression-bonded, and a resin for a low barrier film and a barrier layer is used. If they are the same, the adhesion between layers will be strong, so the delamination force cannot be made weaker than the other delamination forces, but if not so, both resins are not particularly limited.

Another method is so-called pressure bonding while melt extruding a low-density polyethylene, a linear low-density polyethylene, an ethylene vinyl acetate copolymer or a blended product thereof as an intermediate layer between the low barrier film and the barrier layer. It is a method of extrusion sandwich lamination.

At this time, it is necessary to apply an anchor coating agent on the barrier layer side or to make a resin having good compatibility with the extruded resin on the surface so that the surface of the intermediate layer can be strongly adhered. On the low barrier film side, it is necessary that the resin having poor compatibility with the extruded resin is present on the surface so that the peel strength with the intermediate layer is weaker than the peel force between other layers.

It is sufficient that the low barrier film and the barrier layer can be peeled off at the interface between them, but generally, the pulling speed is 200 m.
It is preferable that the adhesive strength as measured by m / min and 180 ° peeling is 5 to 200 g / 15 mm width.

Here, when the films are stuck together, the low barrier film varies depending on the material and the thickness. For example, the unstretched film is stretched even after being stuck by drawing a draw ratio of about 1.03 to 1.20. If residual stress is left in the low barrier film, the low barrier film remaining in the container after peeling will be in a taut state, which is preferable in terms of appearance.

In order to obtain a taut state, the pulling direction is preferably not only the flow direction of the low barrier film but also the width direction. Further, as the degree of residual stress, it is preferable that after the barrier film is peeled, there is a shrinkage of 2% or more in one direction at room temperature and no load from the dimension before peeling.

When the ink containing the release agent is partially printed, it does not adhere to the ink and can be used as a peeling port.
The ink containing the release agent is an ink in which a silicone-based release agent, a fluorine-based release agent, or another organic release agent is dissolved in an amount of 5% by weight or more, and can be printed on a low barrier film or a barrier layer. If there is no particular limitation.

The container body which can be used with the thus obtained lid for gas pack packaging according to the present invention is preferably one which can be heat-sealed with a low barrier film. When the low barrier film is polyethylene, the inner surface to be the sealing surface is polyethylene,
When the low barrier film is polypropylene, the inner surface of the sealing surface is polypropylene, and when the low barrier film is polyvinyl chloride, the inner surface of the sealing surface is also polyvinyl chloride.

[0023]

【Example】

Examples 1 to 8 As low barrier film LLDPE: Linear low density polyethylene (thickness 30 μ) CPP: Non-stretched polypropylene (thickness 30 μ) Perforated CPP: Perforated non-stretched polypropylene (thickness 30)
μ) Pore diameter 0.1 mm (interval 10 × 20 mm) Perforated LLDPE: Pore open linear low density polyethylene (thickness 30 μ) Pore diameter 0.5 mm (interval 10 × 20 mm) Perforated PET / PE: Perforated polyethylene terephthalate 12 μ / low Density polyethylene 30μ Dry Laminated product Pore diameter 0.2 mm (spacing 10 × 20 mm) All the above perforated films are produced by the hot needle melting method.

EVAS: self-adhesive ethylene vinyl acetate copolymer film (thickness 15 μ) PVCS: self-adhesive polyvinyl chloride film (thickness 1)
5μ) As a barrier layer MLEVOH: ethylene vinyl acetate copolymer saponified product /
Nylon / Adhesive layer / Low density polyethylene coextrusion film (total thickness 80μ) CPA: Non-stretched nylon film (thickness 40μ) As outer layer OPET: Biaxially stretched polyethylene terephthalate film (thickness 12μ) Using the above layers, The low barrier film and the barrier layer were corona treated under the following conditions and thermocompression bonded. Further, the barrier layer and the outer layer were laminated with an adhesive by a usual dry laminating method to manufacture a lid member for a gas pack shown in Table 1.

(Corona treatment conditions) Generator VETAPHON ε-TREATER 4kw treatment output Ethylene vinyl acetate copolymer saponification product (hereinafter EVOH surface) 1.2kw CPA surface 1.2kw CPP surface, perforated CPP 1.0kw LLDPE surface, Perforated LLDPE 0.8kw EVAS surface 0.8kw PVCS surface 1.0kw Processing speed 15m / min Thermocompression bonding pressure 10kg / cm Thermocompression bonding temperature EVOH surface and LLDPE surface 90 ° C CPA surface and CPP surface 100 ° C.

At this time, in Examples 2 and 5, a gravure ink containing 20% of silicone oil as a release agent was applied in stripes on the barrier layer side so that the tongue-like portion was located at this application portion. The film was punched out to obtain a lid for gas pack packaging.

Table 1 The lid materials for gas pack packaging of Examples 1, 2, 4, 5, and 7 obtained under the above conditions were made into high-impact polystyrene (hereinafter referred to as H
IPS) / EVOH / low density polyethylene (hereinafter LDP
E (inner surface) configuration, Examples 3 and 6 are HIPS / EVOH
/ CPP (inner surface) constitution, and Example 8 is polyvinyl chloride (hereinafter PVC) / polyvinylidene chloride (hereinafter PVDC)
Each of the vacuum forming trays of PVC / PVC structure is filled with raw beef and replaced with nitrogen, heat sealing temperature 150 ° C., pressure 2
Heat sealing was performed at kg / cm @ 2 and a sealing time of 2 seconds. In this state, the raw beef was blackish red.

When the tongue-shaped portion formed by punching out the film was picked and the film was peeled from the tray, the low barrier film broke from the end of the seal portion in all of Examples 1 to 8 and thereafter the barrier layer had a low barrier. After peeling from the film, only the low barrier film remained on the tray, and the packaged raw beef turned bright red in about half a day.

Further, in Examples 2 and 5, the barrier layer was peeled from the low barrier film by only slightly scratching the tongue-like portion, and only the barrier layer side could be pinched, so that peeling was easy.

Examples 9 to 16 Next, LLDPE, CPP, perforated LLDPE and perforated CPP as a low barrier film, and M as a barrier layer.
Using LEVOH and CPA and OPET as the outer layer, dry laminating the outer layer and the barrier layer, and corona-treating the low barrier film on the barrier layer under the same conditions as in Examples 1 to 8 Tables 2 to 9 show Examples 9 to 16 of the lid materials for gas pack packaging obtained by laminating them in a state of being stretched 1.03 times and 1.07 times in the direction.

In order to check the degree of residual stress in these examples, 10c in the flow direction of the low-barrier film before peeling was used.
Marks at m intervals were attached, and when peeling was performed at room temperature for 1 minute after peeling and the percentage of shrinkage was measured, it was 2 to 4% after peeling, as shown in Table 2.

Table 2 Examples 9, 10, 13, and 14 in Table 2 above are HIPS / E.
Examples 11, 12, of VOH / LDPE (inner surface) configuration
Nos. 15 and 16 are HIPS / EVOH / CPP (inner surface) vacuum forming trays filled with raw beef and replaced with nitrogen, heat sealing temperature 150 ° C., pressure 2 kg / cm 2
Then, heat sealing was performed with a sealing time of 2 seconds. In this state, the raw beef was blackish red.

When the tongue-shaped portion formed by punching out the film was picked and the film was peeled from the tray, the low barrier film broke from the end of the seal portion in each of Examples 1 to 8, and thereafter the barrier layer had a low barrier. After peeling from the film, only the low barrier film remained on the tray, and the packaged raw beef turned bright red in about half a day.

Of these, after peeling off the barrier layer in Examples 9 and 13, the remaining low barrier film LLDPE having a draw ratio of 1.03 was slightly slack in appearance, but Examples 10 to 12 and 14 ~ 16 LLD with draw ratio 1.07
PE and CPP having a draw ratio of 1.03 and 1.07 were both kept taut and were preferable in appearance.

Examples 17, 18 Using CPP as a low barrier layer, perforated CPP, MLEVOH as a barrier layer, and OPET as an outer layer, an anchor coating agent was applied to the EVOH surface of the barrier layer dry-laminated to the outer layer, and the resin temperature was adjusted. LDP melted at 300 ° C
E is extruded between CPP film and pressure bonded, and so-called sandwich lamination is performed at a laminating speed of 60 m / min.
The obtained lid materials for gas pack packaging Examples 17 to 18 are shown in Table 3.
Shown in.

At this time, silicone oil 20 is used as a release agent.
% Or 30% of gravure ink was applied on the barrier layer side in a stripe shape, and the film was punched out so that the tongue was positioned at this applied portion to form a lid for gas pack packaging.

Table 3 The gas pack packaging lid material Example 17 shown in Table 3 is HIPS.
Example 18 of HI / EVOH / CPP (inner surface) configuration
Each PS / EVOH / LDPE (inner surface) vacuum forming tray was filled with raw beef and replaced with nitrogen, heat sealing temperature 150 ° C., pressure 2 kg / cm 2, sealing time 2
Heat sealed in seconds. In this state, the raw beef was blackish red.

The barrier layer can be peeled from the low barrier film by only slightly peeling the tongue, and only the barrier layer side can be pinched. After that, the barrier layer is peeled from the low barrier film and only the low barrier film is peeled off. The raw beef packaged in the tray remained bright red in about half a day.

In particular, the perforated PET / PE of the low barrier film of Example 18 cannot be broken by simply pulling the tongue.
It is preferable to be able to pinch only the barrier layer side from the tongue.

[0040]

EFFECT OF THE INVENTION Since the lid material for packaging a gas pack of the present invention comprises a low barrier film and a barrier layer which are releasably attached to each other, the shelf life of raw meat can be extended by using the lid material. The barrier layer lined with the outer layer can be surely peeled off at the retail store on the day, and bright red meat and the like can be provided. As a result, the meat can be packed by the meat maker, and the packing staff at the retail store is not required. In addition, it can be peeled off and displayed as much as necessary according to the sales volume of the day, which reduces waste in purchasing the product.

Claims (1)

[Claims] 1. A lid material for gas pack packaging, comprising a low barrier film and a barrier layer releasably attached to each other.