JP5400646B2 - Food containers using biaxially stretched multilayer film - Google Patents

Description

  The present invention generally relates to a food packaging container, and more specifically to a food packaging container formed by drawing and imparted with a cut property.

  FIG. 5 is a cross-sectional view of a conventional food packaging container 10 for ham packaging, for example. The food packaging container 10 is composed of a deep-drawn bottom material film 8 that houses ham and a lid material film 9 that is closed from above. The contents 11 such as ham are accommodated in the space portion of the deep-drawn bottom material film 8. The bottom film 8 is mainly composed of a PET or nylon base layer, a barrier layer formed of a saponified ethylene vinyl acetate copolymer, and an easy peel layer formed of an olefin sheet, which are laminated in order. The film is formed by deep drawing. The lid film 9 is mainly formed with linear low density polyethylene (LLDPE layer, hereinafter abbreviated as LL layer) on one side of a PET layer on which a silicon oxide layer as a metal deposition layer is deposited, OPP (biaxially stretched polypropylene film) is laminated on the surface. The easy peel layer side of the bottom material film 8 and the LL layer side of the lid material film 9 are attached to form a food packaging container 10.

  However, in the conventional food container shown in FIG. 5, the bottom film 8 is an unstretched film, and although the deep drawability is good, it is difficult to tear, so a method of tearing the bag and taking out the contents cannot be adopted. It was. In addition, the thickness (the thickness of the bottom material film 8 is 100 μm and the thickness of the lid material film is 82 μm) is large, which is costly and increases the amount of waste.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a food packaging container to which a cut property is imparted while maintaining a certain squeezability.

  Another object of the present invention is to provide a food packaging film that contributes to a reduction in the amount of waste.

  A container for food packaging according to the present invention is a laminate of a biaxially stretched multilayer film comprising at least four layers having a polyamide layer, a barrier layer, an adhesive layer and a seal layer and at least a uniaxially stretched polyester film, polypropylene film or polyamide film. A bottom material film formed of a film for food packaging and a lid material film, wherein the bottom material film is formed by drawing, and obtained by pasting the lid material film on the seal layer side of the bottom material film. It is done.

  The container for food packaging according to the present invention is a laminated film obtained by laminating a biaxially stretched film and an unstretched film, and one of the biaxially stretched film and the unstretched film has a lid material film having a barrier property.

  The food packaging container according to the present invention is also a laminated film obtained by laminating a biaxially stretched multilayer film having a polyamide layer, a barrier layer, an adhesive layer, and a seal layer and at least a uniaxially stretched polyester film, polypropylene film, or polyamide film. The cover material which consists of.

  According to the present invention, since the biaxially stretched multilayer film is biaxially stretched, the strength is increased and the cut property is improved. Furthermore, a certain barrier property can be maintained without being extremely thinned partially in the drawing process.

  As a method for producing these biaxially stretched multilayer films, known lamination techniques can be used, but biaxial stretching by a coextrusion method is desirable from the viewpoint of imparting cutability (tearability) and cost.

The biaxially stretched multilayer film has a polyamide layer, a barrier layer, an adhesive layer, and a seal layer.
A four-layer structure of polyamide layer / barrier layer / adhesive layer / seal layer and a five-layer structure of polyamide layer / barrier layer / polyamide layer / adhesive layer / seal layer can be exemplified. A five-layer structure is preferable in that the deterioration of the barrier property due to pinholes is suppressed.

  For the polyamide layer in the biaxially stretched multilayer film of the present invention, a mixture of an aliphatic polyamide resin such as nylon 6, a semi-aromatic polyamide resin and / or an amorphous polyamide resin can be used. Here, examples of the semi-aromatic polyamide resin include polymetaxylylene adipamide synthesized from metaxylylenediamine and adivic acid, and examples of the amorphous polyamide resin include terephthalic acid and / or A polycondensate of isophthalic acid and hexamethylenediamine can be exemplified.

  The barrier layer in the biaxially stretched multilayer film of the present invention uses saponified ethylene-vinyl acetate copolymer (EVOH). This saponified ethylene-vinyl acetate copolymer (EVOH) has an ethylene content of 20 Those having ˜65 mol% and a saponification degree of 90% or more are preferred.

  A modified polyolefin resin is used for the adhesive layer in the biaxially stretched multilayer film of the present invention. Examples of modified polyolefin resins include ethylene homopolymers, copolymers of ethylene and other olefins, or copolymers of ethylene and other vinyl monomers, such as maleic acid, fumaric acid, acrylic acid, etc. Examples thereof include a polymer graft-modified with an appropriate unsaturated carboxylic acid or an acid anhydride thereof.

  A polyolefin resin is used for the seal layer in the biaxially stretched multilayer film of the present invention. Examples of polyolefin resins include polyethylene resins of various densities (branched low density polyethylene, linear low density polyethylene, medium density polyethylene, etc.), ionomer resins, ethylene-acrylic acid copolymers, ethylene-vinyl acetate copolymers, etc. Can be illustrated.

  Specific examples of the biaxially stretched multilayer film include a HEPTAX OH type manufactured by Gunze Co., Ltd.

  A preferred food container of the present invention is a biaxial structure in which a polyamide layer is laminated on the first layer, a barrier layer on the second layer, a polyamide layer on the third layer, an adhesive layer on the fourth layer, and a seal layer on the fifth layer. A base material film formed of a laminated film obtained by laminating a stretched multilayer film and a polyester film, a polypropylene film or a polyamide film which is at least uniaxially stretched as a front substrate on the first layer side of the biaxially stretched multilayer film; A lid material film, the bottom material film is drawn, and the lid material film is attached to the seal layer side of the fifth layer of the bottom material film.

  In this case, a laminated film obtained by laminating a biaxially stretched film and an unstretched film can be used as the lid material film. Either the biaxially stretched film or the unstretched film has a barrier property. The container for food is formed by bonding the seal layer side of the fifth layer of the bottom material film and the unstretched film side of the lid material film. A film having an easy peel property can also be used for the seal layer.

  Examples of the biaxially stretched film include PET films deposited with inorganic materials, K-coated PET films, OPP films, nylon films, and the like. Specific examples include GL-AE manufactured by Toppan Printing Co., Ltd., TL-HP manufactured by Tosero Co., Ltd., and Senesi KET1000 manufactured by Daicel Value Coating Co., Ltd. Examples of the unstretched film include unstretched PP film, polyethylene film, barrier sealant film, and easy peel film. Specifically, T.C. manufactured by Tosero Co., Ltd. U. Illustrate X FC-S, LL-XMTN manufactured by Futamura Chemical Co., Ltd., Tosero Co., Ltd. S, Futamura Chemical Co., Ltd. FHK2-L, TX254 manufactured by DIC Corporation, and IMX manufactured by J-Film Corporation. be able to.

  Also, as a cover film, a biaxially stretched multilayer film in which a first layer is a polyamide layer, a second layer is a barrier layer, a third layer is a polyamide layer, a fourth layer is an adhesive layer, and a fifth layer is a seal layer. And a laminated film obtained by laminating at least uniaxially stretched polyester film or polypropylene film as a front substrate on the first layer side of the film, and both the above-mentioned lid film and bottom film may be used. The seal layer side of the fifth layer is bonded to each other.

  However, with this construction, the adhesive strength of the bottom film and the lid film is increased and it is difficult to peel off each other, so a notch for easily tearing and opening the container at a part of the end of the container To make it easier to remove the contents by tearing from the notch part, or by processing the edge of the container with a jagged edge, making it easier to tear from anywhere on the jagged edge to make it easier to take out the contents .

  In addition, when easy peelability is imparted to the polyolefin resin layer of the lid material film in the range where the cutability is not affected in the same manner as in the conventional structure, it can be opened from the seal portion as well as in the conventional manner.

  Specific examples of the polyester film stretched at least uniaxially include FE2001 manufactured by Futamura Chemical Co., Ltd. and E5100 manufactured by Toyobo Co., Ltd. Moreover, as a polypropylene film stretched at least uniaxially, specifically, P2161 manufactured by Toyobo Co., Ltd., U-1 manufactured by Toro Cello Co., Ltd., and MCMD-AS manufactured by Futamura Chemical Co., Ltd. Can do.

  Since the food packaging container according to the present invention uses a biaxially stretched film, the container has high strength and excellent cutability. Moreover, since the polyamide layer resistant to impact is incorporated, impact resistance is enhanced, the total thickness of the bottom film can be reduced, and the weight of the food packaging container can be reduced.

It is sectional drawing of the container for food packaging which concerns on Embodiment 1 of this invention. It is sectional drawing of the cover material and bottom material which comprise the container for food packaging which concerns on Embodiment 1. FIG. (A) It is a perspective view of the container for food packaging which provided the notch based on Embodiment 1. FIG. (B) It is a perspective view of the container for food packaging which has a jagged end part based on Embodiment 1. FIG. It is sectional drawing of the cover material and bottom material which comprise the food packaging container which concerns on Embodiment 2. FIG. It is sectional drawing of the conventional container for food packaging.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The thickness of each film used in the present invention is preferably thinner than the improvement in cutability and the reduction in the amount of waste, but is not particularly specified.

  FIG. 1 is a cross-sectional view of a food packaging container according to Embodiment 1 of the present invention. Referring to FIG. 1, a food packaging container 10 according to the present invention includes a bottom material film 8 and a lid material film 9 formed by drawing. The bottom film 8 is drawn in the space so that, for example, four sliced hams can be accommodated using a vacuum packaging machine.

  FIG. 2 is a cross-sectional view of a bottom material film and a lid material film constituting the food packaging container according to the first embodiment. Referring to FIG. 2 (B), the bottom film 8 has a polyamide layer as the first layer, a barrier layer as the second layer, a polyamide layer as the third layer, an adhesive layer as the fourth layer, and a seal as the fifth layer. A biaxially stretched multilayer film 1 (20 μm) in which polyolefin layers as layers are sequentially laminated is laminated with a biaxially stretched polyester film 6 (12 μm) or a biaxially stretched polyamide film (15 μm). The sealing layer side of the biaxially stretched multilayer film is attached to the lid material film 9 by heat sealing.

  Referring to FIG. 2A, a lid material film 9 is formed by laminating a biaxially stretched polyester film (12 μm) or a biaxially stretched polypropylene film 3 (30 μm) on a biaxially stretched multilayer film 1 (20 μm). Is used. In the case of such a configuration, the lid material film 9 and the bottom material film 8 are not easily peeled off, so that there is no easy peel property. However, referring to FIG. 3 (A), a notch 14 is provided in a part of the end of the container so that the container can be easily torn and opened, whereby the container 11 is torn from the notch 14 and the contents 11 are taken out. be able to. In addition, referring to FIG. 3B, by processing the end portion of the container with a serrated blade, it is easy to tear from anywhere on the serrated end portion 13 and the contents can be easily taken out.

(Embodiment 2)
FIG. 4 is a cross-sectional view of a bottom material film and a lid material film used in the food container according to Embodiment 2. The food container is composed of a bottom film 8 and a cover film 9 which are drawn and formed in the same manner as shown in FIG. The bottom film 8 is drawn so that, for example, four sliced hams can be accommodated. The space portion of the bottom material film 8 formed by drawing is filled with contents 11 such as ham using a vacuum packaging machine.

  Referring to FIG. 4B, the bottom material film 8 is formed by laminating a biaxially stretched polyester film 6 or a biaxially stretched polyamide film on a biaxially stretched multilayer film 1, and biaxially stretched. The seal layer side of the fifth layer of the multilayer film is attached to the lid material film 9 by heat sealing.

  With reference to FIG. 4 (A), the cover material film 9 is formed with an olefin sheet on one surface of a biaxially stretched polyester film 2 (12 μm) on which silicon oxide, which is a vapor deposition layer, is deposited, as an example of the configuration. A configuration in which the easy peel layer 5 (25 μm) formed is formed. The easy peel layer 5 side of the lid film 9 is attached to the bottom film 8. Since the lid material film 9 and the bottom material film 8 are pasted via the easy peel layer 5, the contents 11 can be easily taken out by peeling them off. Moreover, the bottom material film 8 is a biaxially stretched film, has improved cutability, and can tear the end of the container with a finger to take out the contents.

  Examples will be described below.

  The composition of the lid and bottom material is summarized in Table 1. The symbols in Table 1 represent each film as follows.

OH: Biaxially stretched multilayer film (biaxially stretched film of 5 layers comprising polyamide layer / barrier layer / polyamide layer / adhesive layer / seal layer)
Transparent vapor deposition OPET: Biaxially stretched polyester film OPP having a vapor deposition layer OPP: Biaxially stretched polypropylene film OPET: Biaxially stretched polyester film Easy peel: Easy peel layer PET: Polyethylene terephthalate resin layer NY: Polyamide resin layer EVOH: Ethylene-vinyl acetate Copolymer saponified resin layer # symbol represents a film thickness (μm). The symbol // indicates the dry laminate part, and / indicates the boundary of the resin by coextrusion.

(Dry laminate)
Between each film, an adhesive A-159 (manufactured by Dainichi Seika Kogyo Co., Ltd.) was used, and dry lamination was performed at a coating amount of 2.5 g / m ² .

(Food containers)
Use MULTIVAC R245 (manufactured by Tokyo Food Machinery Co., Ltd.) as a deep-drawing packaging machine, draw the bottom material under 85 ° C condition, fill the contents and vacuum process, and then cover with lid material at 130 ° C for 1 second. Sealed.

  Examples and Comparative Examples were evaluated as follows, and the results are shown in Table 2.

(Puncture strength)
It measured based on JISZ-1707. Made from the outside.
For the lid material, 7N or more was judged as appropriate ○, and less than 7N was judged as inappropriate ×.
In order to narrow down the bottom material, a certain degree of strength is required before narrowing down.

(Oxygen permeability)
It measured based on JISK-7126-2. Less than 30 ml / m ² · d · MPa was deemed appropriate ○, and 30 ml / m ² · day · MPa or more was deemed inappropriate ×.

(Tear strength)
It measured based on JISK-7128 in the state which sealed the bottom material and the cover material.
The measured value was not the numerical value per thickness (N / cm) but the maximum tear load (N).
Less than 15N was determined to be appropriate ○, and 15N or more was determined to be inappropriate ×.

  In the above embodiment, sliced ham is exemplified as the food. However, the present invention is not limited to this, and frozen food, retort food, boiled food, raw meat, various processed foods, gas packs that are highly sensitive to oxygen gas. It can be preferably applied to any food such as food for frozen storage, and can be prevented from being deteriorated by oxygen gas.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The food packaging container of the present invention can improve cutability, and further realize cost reduction and reduction of waste due to weight reduction and thinning.

DESCRIPTION OF SYMBOLS 1 Biaxially stretched multilayer film 2 Biaxially stretched polyester film 3 having a vapor deposition layer 5 Biaxially stretched polypropylene film 5 Easy peel layer 6 Biaxially stretched polyester film 8 Bottom material film 9 Cover material film 10 Food packaging container 11 Contents 13 Jagged Shape end 14 Notch (notch)

Claims (4)

A bottom film formed of a film for food packaging formed by laminating a biaxially stretched multilayer film having a polyamide layer, a barrier layer, an adhesive layer and a seal layer and at least a uniaxially stretched polyester film, polypropylene film or polyamide film;
A cover material film,
The bottom material film is drawn,
A container for food packaging, wherein the lid material film is attached to the seal layer side of the bottom material film.   The container for food packaging according to claim 1, wherein the lid film is a laminated film obtained by laminating a biaxially stretched film and an unstretched film, and one of the biaxially stretched film and the unstretched film has a barrier property.   2. The laminated film obtained by laminating the biaxially stretched multilayer film having a polyamide layer, a barrier layer, an adhesive layer and a seal layer and a polyester film, a polypropylene film or a polyamide film stretched at least uniaxially. Food packaging container.   The biaxially stretched multilayer film has a five-layer configuration in which a polyamide layer is laminated on the first layer, a barrier layer on the second layer, a polyamide layer on the third layer, an adhesive layer on the fourth layer, and a seal layer on the fifth layer in this order. The food packaging container according to claim 1, which is a film.

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