JPS6235840A - Packing-material laminated film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a grain layer film for packaging, and more specifically, it has a high barrier property, can be packaged by vertical automatic filling, and has a high temperature sterilization treatment condition. The present invention relates to a packaging laminated film that is particularly suitable for retort sterilization packaging.

[Prior Art] Currently, J! J hand aluminum foil (7~20 lm
) There is a plastic laminate with the following layer structure.

■ PHT/AI! Foil/GPP ■PET/AI! Foil/0-Ny/cppPET
: Polyethylene tereftate layer cpp : Unstretched polypropylene layer o-sy : Stretched orientation 86-nylon, 6-nylon These plastic laminates have high barrier properties, high strength, heat sealability, etc. It can be used as a packaging material for retort sterilization packaging.

[Problems to be Solved by the Invention] However, when these plastic laminates are automatically filled using a vertical automatic filling machine, they tend to fold when passed through a sailor as shown in Fig. 1 as shown in Fig. 2. Although the aluminum foil has wrinkles (there are folds and wrinkles in part A in Figure 2, and many cracks can be seen in the aluminum foil at this wrinkled area), and aluminum foil with good barrier properties was used,
This poses a problem in that water vapor and oxygen pass through the rack, and the appearance is impaired.

LMeans and effects for solving the problem A packaging laminated film characterized by having an unstretched polypropylene film layer via a barrier layer consisting of the following is provided.

In the present invention, the film having heat resistance of 130° C. or higher is preferably a thermoplastic resin film, and specific examples include aromatic polyester films such as polyethylene terephthalate film and polybutylene ethylene terephthalate film; Raw nylon film, 6
- Nylon films such as nylon films are preferably used. Polycarbonate resin films can also be used.

Here, “having heat resistance of 130°C or higher” means AS
This means that the Vicat softening point in the heat resistance test of TM-D-1525 is 130°C or higher. Also, 130
As the heat-resistant film below -L, it is preferable to use a film that has particularly high barrier properties and is not hygroscopic. In this respect, the above-mentioned aromatic polyester film is particularly preferred.

If the thickness of the film layer having heat properties of 130°C or more is too thin, the strength of the film layer will be insufficient, and the metal P
The protection of the VD layer becomes insufficient, and the metal PVD layer is easily destroyed by external force, and when destroyed, the barrier properties based on the metal P'VD layer tend to deteriorate rapidly. Also,
If the thickness of the film layer that is heat resistant to 130°C or more is too thick, the entire laminated packaging film becomes stiff and lacks flexibility even if it is filled and packaged using a vertical filling machine, as shown in Figure 2. The bending of the sailor at part A causes creases, which may induce destruction of the metal PVD layer.Furthermore, when heat-sealing, it becomes difficult for heat to be transmitted, making it difficult to heat-seal properly. For this reason, the thickness of the film layer having heat resistance of 130° C. or higher is preferably 10 to 2 cm.

The metal PVD layer is formed by carrying out an anchor coating treatment on one side of the film having heat resistance of 130° C. or higher, if necessary, and then subjecting the anchor coated surface to a metal PVD treatment.

Methods for forming the metal PVD layer include vacuum evaporation, reactive evaporation, sputtering, reactive sputtering,
Conventional PVD (Physical Paper Deposition: Physical Vapor Dep.
A thin film forming method classified as a method (position method) is employed.

In the present invention, the metal PVD layer is a thin film layer of an inorganic metal compound formed by the PVD method as described above, and specific examples include aluminum, silicon, titanium, tin, selenium,
Examples include thin FMJ layers mainly made of magnesium, barium, indium, calcium, zirconium, thorium, thallium, tantalum, zinc, or oxides, halides, and nitrides of these alone or in mixtures.

If the thickness of the metal PVD layer is too thin, high barrier properties may be exhibited; if it is too thick, the rigidity of the metal PVD layer becomes too large and cannot follow bending, resulting in damage such as cracks, resulting in poor barrier properties. This may lead to a sudden decrease in For this reason, the thickness of the metal PVD layer is 30
It is preferable to set it as 0-100OA.

In the laminated film of the present invention, probably metal PVD
It is thought that because the layer is thin, it expands and contracts following the other plastic layers during retort heat treatment, thereby ensuring barrier properties without generating cracks. Note that it is preferable that the surface of the metal PVD layer be as smooth as possible.

For the barrier layer made of barrier resin, vinylidene chloride resin, aromatic polyester such as polyethylene terephthalate, polybutylene terephthalate, 6-row nylon, 6-nylon, etc. are used, but this barrier layer is formed on the inner surface of the laminated film. Since it is a layer that exists, mechanical strength is not so necessary, and in that sense, vinylidene chloride resin is preferable because it has good barrier properties and is inexpensive.

It is particularly preferable to use an unstretched vinylidene chloride resin film as the vinylidene chloride resin layer.

The unstretched vinylidene chloride resin film is produced by casting vinylidene chloride resin, is unstretched and unoriented, hardly shrinks even when heated, and has excellent flexibility. Here, the vinylidene chloride resin is a copolymer resin obtained by copolymerizing vinylidene chloride with one or more comonomers selected from vinyl chloride, acrylonitrile, methyl methacrylate, ethyl acrylate, vinyl acetate, methacrylic acid, etc. is preferred. From the viewpoint of ensuring barrier properties, it is preferable that vinylidene chloride be present in the vinylidene chloride resin in an amount of 50 mol % or more.

If the thickness of the unstretched vinylidene chloride resin film layer is too thin, the barrier properties will be insufficient, and more water vapor and oxygen will permeate to the metal PVD layer side. The high barrier properties of the layer tend to deteriorate rapidly. From this, the thickness of the unstretched vinylidene chloride resin layer is preferably 20 gm or more, more preferably 20 to 50 ALm.

Films formed from vinylidene chloride resin latex undergo whitening during retort heat treatment, which is undesirable in terms of appearance, while stretched vinylidene chloride resin films develop shrinkage wrinkles during retort heat treatment, resulting in a decrease in appearance and strength.

The barrier layer made of a barrier resin may be a single layer, or may be a laminate of two or more layers.

Note that when only a metal PVD layer is used and no barrier layer is used, the barrier properties due to retort heat treatment are insufficient, so the presence of a barrier layer is essential.

The unstretched polypropylene layer gives the packaging laminated film heat sealability, strength, and strength during retort heat treatment (sheet breaking strength due to expansion of contents during retort treatment at 130°C).The unstretched polypropylene film itself It is obtained by molding polypropylene resin by casting. As the polypropylene resin, in addition to a propylene homopolymer, a copolymer obtained by copolymerizing propylene with a small amount of como/mer can also be used. From the viewpoint of heat resistance, a polymer with a small amount of comonomer components and crystallinity close to a homopolymer is preferable.

The unstretched polypropylene resin layer does not undergo thermal shrinkage because it is not oriented by stretching.

If the thickness of the unstretched polypropylene film layer is too thin,
As the heat-sealing strength decreases, the strength of the laminated film also tends to decrease, and if it is too thick, the amount of heat required for heat-sealing increases, making heat-sealing even more difficult.

Furthermore, the thermal expansion of the polypropylene film layer increases during retort treatment, which tends to have an adverse effect on the metal PVD layer. For these reasons, the thickness of the unstretched polypropylene film layer is preferably 40 to 100 g.

The packaging material laminated film of the present invention is manufactured, for example, as follows.

(2) First, a metal PVD layer is formed on one side of a film having heat resistance of 130° C. or higher. Here, before forming the metal PVD layer, it is preferable to perform an anchor coating treatment on the film surface with a highly heat-resistant anchor coating agent.

(2) Next, an adhesive is applied to the metal PVD layer to form an adhesive layer, and an unstretched vinylidene chloride resin film is bonded to the surface of this adhesive layer.

(2) Next, an adhesive is applied to the surface of the unstretched vinylidene chloride resin film to form an adhesive layer, and an unstretched polypropylene film is bonded to the surface of this adhesive layer.

Further, instead of laminating in the order of (1) and (2) above, it is also possible to manufacture by laminating in the order of (1) and (2).

Here, as the anchor coating agent mentioned in the above (①), a highly heat-resistant urethane-based anchor coating agent shows particularly favorable results.Also, as the adhesive used in the adhesive layer, a retort coating agent at 120 to 130°C is recommended. Adhesives whose adhesive performance does not deteriorate under the processing conditions are used; highly heat resistant urethane adhesives give particularly favorable results.

Next, a specific example of the layer structure of the packaging laminated film of the present invention will be shown, however, each layer will be abbreviated as follows.

PET: Polyethylene terephthalate layer A!・
vM: Aluminum vapor deposited film pvoc: Unstretched vinylidene chloride resin film layer CPP: Unstretched polypropylene film layer LPE
↑2 Polyethylene terephthalate layer with fine satin texture unevenness on the surface 0-Ny: Biaxially stretched oriented nylon layer/: Anchor coat layer/: Adhesive layer (1) PET/Af-VNIPVDCICPP (2)
M-PET/PE↑/AN-VM/PVDC/C:P
P(3) 0-N7/PET/AJ)-VNIPVDC
ICPP(4) CPPIPET/Al-VNIPV
DCICPP (5) PET/Af・VM/PVDC10
-My/CPP(6)PET/AR-VM/PVDC/
PET/CPP(7) LPET/PET/Ai'・
VM/PVDC/PE/CPP(8) LPET/P
ET/AI!・VM/PVDC: 10-N! /CPP Among the above specific examples, (1) has PET on the outside and CPP.
An excellent retort packaging material can be obtained by heat-sealing the CPP surface with the inner side (the surface in contact with the object to be filled).

Ensure strength through PUT.

AI!・V)l ensures a high level of barrier properties, is flexible, does not generate cracks even when bent, etc., and maintains its barrier properties.

The CPP layer ensures heat sealability, acid resistance, chemical resistance, and mechanical properties. Also, p V D C'
! , < ensures barrier properties, so water vapor from the contents of the retort package is absorbed from the inside of the package^i) -V
M.

AI without violating layers! - The barrier properties of the vM layer can be maintained, and the contents of the package will not be altered.

The laminate of (2) is made by laminating M-PET on top of (1), and by turning the finely textured uneven surface of M-PET outward, the surface has good slipperiness and improves workability. It becomes a packaging film. Furthermore, since there are two layers of PET/PET with excellent heat resistance and mechanical strength, the packaging material film has excellent strength at high temperatures.

The laminate of (3) is a packaging film in which the laminate of (1) is further laminated with O-N, and the breakthrough strength of the laminate of (1) is improved, and the laminate of (2) is Superior flexibility than laminates.

The laminate (4) is a laminate in which CPP is laminated on the surface of the PET layer of the laminate in (1), and the CPP layer is on both surfaces of the laminate (
Since the heart-sealing property is ensured on both surfaces (inside and outside), it becomes a packaging film that can provide a high-strength bag that can be formed by a so-called envelope pasting method.

The laminate (5) has two barrier layers, (
Furthermore, 0-N is added between the pvoc layer and the GPP layer of the laminate in 1).
One layer is added. Breakthrough strength and barrier properties of the inner surface when one bag is made of c+-sy layer are (1)
There are four types of laminates.

The laminate of (8) is obtained by replacing the 0-N1 layer in the laminate of (5) with a PET layer, and when it is made into a single bag, the strength and barrier properties at high temperatures on the inner side are the same as those of (1). This is an improved packaging film compared to laminates.

The laminate in (7) is the PET laminate in (8))! This packaging film has an M-PET layer laminated on its surface, and is an improved packaging material film with improved surface slipperiness and outer strength when used as a bag.

The laminate of (8) has I on the PET layer surface of the laminate of (5).
This is a packaging film made by laminating PET 5, which is improved in terms of surface slipperiness and outer strength when used as a bag.

[Example] Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A polyethylene terephthalate film with a thickness of 121 L was anchor-coated with a thermosetting urethane-based anchor coat agent, and a thin aluminum film with a thickness of 600 A was entirely formed on the anchor-coated surface by a vapor deposition method.

A non-stretched vinylidene chloride resin film having a thickness of 20 cm was laminated on the surface of the obtained aluminum vaporized layer via a thermosetting urethane adhesive, and further on the surface of the unstretched vinylidene chloride resin film layer. A packaging film was obtained by laminating an unstretched polypropylene film with a thickness of 70 p-m via a urethane adhesive layer.

The above-mentioned packaging film was placed in a vertical filling machine with a part of the membrane as shown in Figure 1, and the test contents were
Water-based foods include vinegar and salad.

Mixture of tomato ketchup in a weight ratio of 1:l:1 600
500 g of curry (cooked) were each filled. The size of the filling body at this time is 230 m in width and 25 m in length.
It was 5 mm. This filling body (backed three-sided seal body) is shown in FIGS. 3(a), (b), and (c).

Retort treatment (130℃ x 45 minutes) for the above packed body
The heat sealability and barrier properties before and after were investigated. The results of heat sealability are shown in Table 1, and the results of barrier property are shown in Table 2.

Example 2 A polyethylene terephthalate film (We'12gm) in which one side of the polyethylene terephthalate layer of the packaging film obtained in Example 1 was made into a finely textured uneven surface by interposing a urethane adhesive layer on the surface of the polyethylene terephthalate layer. They were laminated so that the side surfaces were adhered to obtain a packaging film with good surface slipperiness.

The packaging film was filled using a vertical filling machine in the same manner as in Example 1 to obtain a packed body having the same dimensions as in Example 1.

The physical properties of this packing were investigated in the same manner as in the examples, and the results are shown in Tables 1 and 2.

Table 2 [Barrier properties] [Effects of the invention] The packaging laminated film of the present invention exhibits high barrier properties due to the metal PVD layer, and the metal PVD layer is thin and does not crack even when bent or bent. In addition, it is possible to perform packaging using vertical automatic filling, which enables efficient automatic packaging, and
Metal PVD with barrier layer made of barrier resin
The layer maintains a high level of barrier properties without being attacked by gases, liquids, etc. Furthermore, the unstretched polypropylene film layer exhibits heat sealability and chemical resistance such as acid resistance and alkali resistance against the contents, and the overall property is resistant to high temperatures. It can withstand sterilization treatment conditions and exhibits excellent characteristics, especially in applications for retort sterilization packaging.

[Brief explanation of the drawing]

i1 diagram is 9i! A front view showing a sailor used in a mold movement filling machine, Fig. 2 is an explanatory view showing a state in which the film is bent in a part of the sailor and traveling in the direction of the arrow, and Fig. 3 is a packaging film of the present invention. Fill it with a vertical automatic filling machine,
Fig. 3 (a) shows a packed body that has been heat-sealed.
) is a plan view, FIG. 3(b) is a sectional view taken along the line YY, and FIG. 3(c) is a sectional view taken along the line XX. 1...Sailor, 2...Wrapping material film, 3...Filler, 4...Heat seal portion, 5...Contents.

Claims (1)

[Claims] (1) Having a metal PVD layer on one side of the film having heat resistance of 130°C or higher, and further having an unstretched polypropylene film layer on the upper surface of the metal PVD layer with a barrier layer made of a barrier resin interposed therebetween. Characteristic laminated packaging film.