JPS6052945B2 - Tube-shaped composite film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tubular composite film, and more specifically, it has excellent gas barrier properties, moisture proof properties, pinhole resistance, etc., and even when subjected to the physical effects of bending ability, This invention relates to a tubular composite film that has been improved so that its performance does not deteriorate.

Conventionally, relatively large packaging has been used for products that are susceptible to deterioration due to the effects of humidity and oxygen during storage, in the food field such as chilled beef and other meat products, raw cheese and tea, and in the non-food field such as medicine. As for the materials, there are known materials that are mainly paper materials and laminated with polyolefin resin layers, metal foils, etc. depending on various purposes, or materials that are laminated with various resin layers on polyamide resin layers.

However, since the former is mainly made of paper material, its range of application as a packaging material is narrow and its pinhole resistance is also poor. In addition, the latter may cause a decrease in pinhole resistance as a result of not being able to reliably prevent a decrease in the water content of the polyamide resin layer, and depending on the application, the polyamide resin layer may lack gas barrier properties. There is also. In particular, the former has the disadvantage that its properties such as gas barrier properties, moisture proof properties, and pinhole resistance easily deteriorate due to physical effects such as bending. The present inventors have arrived at the present invention as a result of intensive studies to provide a composite film that solves the above-mentioned conventional drawbacks.The gist of the present invention is to A polyolefin resin layer is formed on the outer surface, and a metal vapor deposited resin layer selected from the group consisting of a metal vapor deposited polyester resin layer, a metal vapor deposited polypropylene resin layer, and a metal vapor deposited polyamide resin layer is formed on the outer surface via an auxiliary agent. It consists of a tubular composite film formed by forming a film. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an example of the tubular composite film of the present invention when it is flattened.

In the figure, reference numeral 1 denotes a polyamide resin layer, on the inner surface of which a polyethylene resin layer 2 is laminated, and on the outer surface thereof a polyethylene resin layer 3 as an auxiliary agent is laminated. This tubular three-layer composite film is a composite film that can be easily obtained by coextrusion (hereinafter referred to as coextrusion film A).On the outer surface of this coextrusion film A,
Furthermore, a metal-deposited polyester resin layer B is formed by vacuum-depositing aluminum metal 6 on one side of the polyester-based resin layer 5 via a polyethylene-based resin layer 4 as an auxiliary agent, with the surface of the metal-deposited metal 6 facing inside. It has been done. That is, since the tubular composite film of the present invention uses the tubular coextruded film A, there is no seam (sealing part) in the extrusion direction (usually the longitudinal direction), so there is no possibility of seal failure or bag breakage. It is difficult to peel off, is easy to handle, and can be made into a packaging bag simply by applying a bottom seal, making it extremely convenient.

In addition, the film of the present invention has a metal vapor-deposited polyester resin layer formed on the outer surface of the polyamide resin layer 1 via a laminating agent, so it has gas barrier properties, moisture proof properties, and even blocks ultraviolet rays. It is also excellent in sex. Further, as shown in FIG. 1, when the vapor-deposited metal is not exposed on the outermost surface, there is no fear that the vapor-deposited metal will be damaged during work or transportation, which is preferable.
In addition, as in the case of the example of the present invention shown in FIG. 1 explained above, the polyethylene resin layer is formed in advance on the outer surface of the polyamide resin layer by coextrusion. When laminating the polyethylene resin layers, the polyethylene resin layer is simply formed on the side of the metal-deposited polyester resin layer as a laminating agent, and the above lamination ends up being a lamination of the polyethylene resin layers. It is advantageous and preferable in terms of lamination molding.

However, there is no need to take the trouble to separately form a polyethylene resin layer on both the polyamide resin layer and the metal-deposited polyester resin layer apart from the co-pressing process; the point is that the polyethylene resin layer only needs to be present as a bonding agent. It is. In the tubular composite film of the present invention, the tubular polyamide resin layer utilizes its excellent gas barrier properties and toughness. Examples are 6, 66,
Examples include nylons 10, 11, and 12 or copolymers of two or more of these, but any material that can be formed into a film is suitable.

In addition, from the viewpoint of molding, it is preferable to use a non-stretched material, but it may be a stretched material. In addition, the polyolefin resin layer formed on the inner surface of the polyamide resin layer prevents changes in the moisture content of the polyamide resin layer, and also serves as an adhesive when molding packaging bags, etc. .

Specific examples include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE) with a density in the range of 0.910 to 0.970.
PE) or blends thereof, copolymer resins, ethylene-vinyl acetate copolymers (EVA), ionomer resins, polypropylene and modified resins thereof, blend resins thereof, adhesive polyolefin resins, and the like. In addition, when forming a resin layer made of representative resins among the above-mentioned polyolefin resins, such as low density polyethylene, medium density polyethylene, and high density polyethylene, on the inner surface of the polyamide resin layer, the above-mentioned adhesives may be used. Resins selected from the group of polyolefin resins such as ionomers, modified polyethylenes, etc. may further be used. In addition, as a laminating agent for the polyamide resin layer and the metal vapor deposited resin layer, the above-mentioned polyolefin resin used for the inner surface of the polyamide resin layer is similarly used, and other materials normally used in the dry lamination method are also used. Polyurethane adhesives, epoxy adhesives, etc. can also be used.

Further, a metal vapor deposited resin selected from the group consisting of a metal vapor deposited polyester resin layer, a metal vapor deposited polypropylene resin layer, and a metal vapor deposited polyamide resin layer formed on the outer surface of the polyamide resin layer via a laminating agent. Since the layer has good gas barrier properties, it is excellent in protecting the packaged items (contents).

Moreover, because of the metal vapor deposited layer provided on the metal vapor deposited resin layer, the composite film of the present invention not only has the above-mentioned gas barrier effect even more remarkable, but also has excellent ultraviolet and visible light blocking properties. It is more suitable for protecting contents.
In addition, the range of application is expanded because it adds decorative properties to the packaging material. In the above metallized resin layer, as the polyester resin, in addition to polyethylene terephthalate made of terephthalic acid and ethylene glycol, polyesters made of phthalic acid such as isophthalic acid and various glycol components can be used, and polypropylene resin As the material, polypropylene and modified products thereof, which are usually used as packaging materials, can be used, and as the polyamide resin, the above-mentioned polyamide resin layer (
For example, those used in the coextrusion film A shown in FIG. 1) can be used in the same manner.

Moreover, these resins are preferably uniaxially or biaxially stretched from the viewpoint of mechanical strength and the like. Moreover, metals such as aluminum, tin, and silver can be used as the vapor-deposited metal. The tubular composite film of the present invention described in detail above has gas barrier properties,
It has excellent moisture resistance and pinhole resistance, and these properties do not deteriorate even if subjected to physical action such as bending repeatedly or for a long time.It also has excellent workability and is widely applicable as a packaging material. has valuable industrial advantages.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example By using a coextrusion method, a polyamide (P
A) A tubular three-layer composite film was molded, each having a 70p thick low density polyethylene (LDPE) layer on its inner surface and a 20μ thick low density polyethylene (LDPE) layer on its outer surface. .

Next, a metal-deposited resin film obtained by depositing aluminum with a thickness of about 0.05 μm on one side of biaxially oriented polyethylene terephthalate (PET) with a thickness of 12 μm using a vacuum deposition method is applied to the outer surface of the deposited aluminum. The composite tube of the present invention was obtained by laminating the tubes on the inside by a polyethylene extrusion sand lamination method (polyethylene thickness: 15 μm). Diameter 80W from this composite tube! I! A sample for oxygen permeability measurement of L and a sample for moisture permeability measurement with a diameter of 60 wrm were taken, and the oxygen permeability and moisture permeability of these samples were measured before and after bending. The results are shown in the table below.

Comparative Example 1 Kraft paper with a thickness of 70 μm and aluminum metal foil with a thickness of 9 μm were combined using a polyethylene extrusion sand lamination method (
A 20μ thick polyvinylidene chloride coated stretched polypropylene layer is laminated on the aluminum metal foil side using a polyethylene extrusion sand lamination method (polyethylene thickness 15μ), and a thick polypropylene layer is laminated on the surface of the polypropylene layer. A comparative composite film was obtained by extrusion laminating a 45μ low density polyethylene (LDPE) layer.

Samples were taken from this composite film in the same manner as in Example 1, and the oxygen permeability and moisture permeability were measured. The results are shown in the table below. Comparative Example 2 By co-extrusion, a 30μ thick unstretched polyamide layer was used as the intermediate layer, a 70μ thick low density polyethylene (LDPE) layer was formed on the inner surface, and a 20μ thick low density polyethylene (LDPE) layer was formed on the outer surface. LDPE) layer for comparison, respectively.
A layered composite tube was obtained.

A sample was taken from this composite tube in the same manner as in Example 1, and the oxygen permeability and moisture permeability were measured. The results are shown in the table below.

As is clear from the table above, the composite tube of the example of the present invention shows no decrease in oxygen permeability or water vapor permeability before and after bending, and there is no occurrence of pinholes, scratches, etc. Moreover, each numerical value is extremely low, making it a good film that can be widely applied to various uses.

The composite film of Comparative Example 1 had good oxygen permeability and moisture permeability before bending, but pinholes occurred in the aluminum foil after bending, and as a result, both oxygen permeability and moisture permeability decreased. However, not only the properties as a film but also the handling properties are extremely poor.

Although the composite film of Comparative Example 2 shows no decrease in either oxygen permeability or moisture permeability between before and after bending, the high numerical values limit the range of application as a film, which is not preferable.

Test method A sample taken from a composite film was folded in half, and then folded in half again (folded into four in total), a 5k9 weight was placed on the sample, a crease was made on the sample, the sample was unfolded, and the test sample was measured according to the following method.

Oxygen permeability: Based on the Seikagaku-style gas permeation test method.

(20'C absolute dry condition) Moisture permeability: JIS
According to ZO2O8.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of the tubular composite film of the present invention. 1... Polyamide resin layer, 2, 3, 4...
...Polyethylene resin layer, 5...Polyester resin layer, 6...Aluminum metal, A...
...Coextrusion composite film, B...Metal-deposited polyester resin layer.

Claims (1)

[Claims] 1 A group consisting of a polyolefin resin layer formed on the inner surface of a tubular polyamide resin layer, and a metal vapor deposited polyester resin layer, a metal vapor deposited polypropylene resin layer, and a metal vapor deposited polyamide resin layer on the outer surface via a laminating agent. A tubular composite film formed with a metal vapor-deposited resin layer selected from.