JP2508764B2 - Easy peeling laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an easily peelable laminated film which is an integrated laminate and which can be easily peeled off under a certain use condition. In particular, the present invention relates to an easily peelable film suitable as a double-wrapping film, which does not normally exhibit air permeability, but can be provided with good air permeability as required.

(Prior Art) Conventionally, a so-called perforated film, which is a synthetic resin film such as a polyethylene film or a polypropylene film, provided with a plurality of through holes for the purpose of providing air permeability, is widely used as a packaging film for fruits and vegetables. in use. In addition, a laminated film obtained by heat-sealing the perforated film with paper (kraft paper, rayon paper, Japanese paper, etc.) or a non-woven fabric, and packaging the Japanese confectionery, desiccant, insect repellent, oxygen scavenger, chemical warmer, etc. It is used as a film for film.

(Problems to be Solved by the Present Invention) However, not only the perforated film having through holes but also the laminated film described above cannot be provided with the moisture-proof property and the gas barrier property. Therefore, a desiccant that dislikes moisture and oxygen before use,
Regarding packaging of contents consisting of active substances such as insect repellents and oxygen scavengers, after packaging the individual contents with perforated film, the individual packages (individual packaging) or multiple packages (aggregate) In addition, packaging is performed by using an exterior film having moisture resistance and gas barrier properties. In such a packaging form, there is a problem that it takes time to wrap, and in particular, in the above-mentioned collective packaging, in order to store the unused individual packages, it is necessary to completely seal them with the exterior film until the packaged items are packaged. There is a problem that various effects possessed by a product are easily lost, and its storage is troublesome.

(Means for Solving Problems) The present invention finds an easily peelable laminated film in which a perforated film having a through hole and a film having no through hole are laminated, and the adhesive strength between both films is in a specific range. If the laminated film is used to form a double-wrapping film, the above problems can be solved, and the gist of the invention is to provide a perforated synthetic resin film having a plurality of through holes 3. 1 and the synthetic resin film 2 which does not have a through hole face each other,
At least one of the facing film surfaces is subjected to corona discharge treatment and then laminated, and the adhesive strength of the interface 4 between the film 1 and the film 2 is set to 5 to 100 g / 20 mm width. It exists in the film.

The present invention will be described below with reference to the drawings. FIG. 1 is a schematic partial cross-sectional view showing an example of the laminated film of the present invention.

The film referred to in the present invention includes an extremely thin film to a large sheet.

Reference numeral 1 in the figure denotes a perforated synthetic resin film, and various synthetic resins can be used for the film, but in particular, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, an ionomer resin, etc. A polyolefin resin film having excellent adhesiveness can be preferably used.

The thickness range of the perforated film 1 is not particularly limited, but a range of 5 μm to 200 μm, preferably 15 μm to 100 μm is preferable, and a thickness of less than 5 μm is easy to tear, and a thickness of more than 200 μm lacks flexibility and is difficult to handle. .

The plurality of through holes 3 provided in the film 1 may have a diameter of about 0.1 to 2 mm and an interval between the holes of about 0.5 to 10 mm, and can be easily provided by piercing with a heating needle.

Further, symbol 2 in the drawing is a synthetic resin film having no through holes, and the resin to be used is not limited, but is selected from polyvinyl chloride resin, polyolefin resin, nylon resin, polyester resin, polycarbonate resin, etc. You can use a single film. Particularly when moisture resistance and gas barrier properties are required, saponified ethylene-vinyl acetate copolymer, polyvinylidene chloride, cellophane,
A composite film having a layered structure of a barrier material such as a metal foil may be used.

The thickness range of the film 2 is not particularly limited, but 5
The range of μm to 300 μm is preferable, and the range of 30 μm to 100 μm is preferable. If it is less than 5 μm, the rigidity is poor, and if it exceeds 300 μm, the flexibility is poor and the film is difficult to peel off.

In the laminated film of the present invention, it is necessary to make the above-mentioned perforated film 1 and film 2 face each other, and perform corona discharge treatment on at least one of the facing film surfaces before laminating.

As a method of corona discharge treatment, a normal corona discharge treatment device having a high-frequency oscillator and an electrode and capable of continuous treatment (treatment by passing a sheet between the corona discharge electrode and the counter electrode) may be used.

In the corona discharge treatment, the treatment conditions such as the corona discharge output and the treatment speed are appropriately adjusted so that the adhesive strength of the interface 4 between the perforated film 1 and the film 2 which are pressure-bonded and laminated becomes 5 to 100 g / 20 mm width. If the adhesive strength of the interface 4 is less than 5 g / 20 mm width, the problem of easy peeling from the interface portion during the winding process after lamination is likely to occur, and if it exceeds 100 g / 20 mm width, it is extremely difficult to peel the film. There is a problem that it is difficult to perform the function of the double packaging film easily.

The adhesive strength is a value measured by a 180 ° peeling test at a take-up speed of 200 mm / min.

The method of stacking films other than the corona discharge treatment of the present invention, such as the dry laminating method and the extrusion laminating method, has the following problems.

(1) At the time of adhesion, it is necessary to apply an anchor coating agent or an adhesive to the perforated film surface, and these materials show through from the through holes, and in the case of a roll, the film cannot be unwound.

(2) An anchor coating agent, an adhesive agent, or the like blocks the through holes, and the original air permeability is impaired.

(3) It is difficult to set the adhesive strength within an appropriate range.

 Hereinafter, the present invention will be described with reference to examples.

(Example) Example (1) Perforated film 1; oriented polypropylene film (thickness 60 μm, hole diameter 0.1 mm, hole interval 1.5 mm) Film 2; coextruded multilayer sheet (thickness 90 μm) having the following constitution (ethylene vinyl acetate copolymer weight) Combined * / acid-modified polyolefin resin / saponified ethylene vinyl acetate copolymer / nylon resin / acid-modified polyolefin resin / ethylene vinyl acetate copolymer) (2) Using the above-mentioned films 1 and 2, perforated film surface and ethylene The vinyl acetate copolymer * surface was subjected to corona treatment under the following conditions and then thermocompression bonded.

Corona discharge treatment conditions; Corona discharge treatment machine (made by VETAPHONE) High-frequency oscillator; High-frequency output display film 1 ... 2.4KW film 2 ... 2.0KW Thermocompression bonding condition; Films 1 and 2 are continuously corona discharge under the above conditions It processed and immediately thermocompression-bonded.

Surface temperature of thermo-compression roll …… 135 ℃ Contact pressure of roll …… 10kg / cm Thermo-compression speed …… 15m / min (3) Laminated film obtained under the above conditions 1,
The interfacial bond strength between the two was 40 g / 20 mm width. In addition, when a small bag for individual packaging for desiccant was created from this laminated film, it showed good moisture resistance before using the desiccant, the film 2 could be easily peeled off if necessary, and good air permeability after peeling. Indicated.

Comparative Example When using the films 1 and 2 used in the examples and thermocompression bonding without corona discharge treatment, the adhesive strength was less than 5g / 20mm width, and the films 1 and 2 were peeled off before use and double-wrapped. It was inconvenient for the film.

(Effects of the Invention) As described above, the laminated film of the present invention can be used as a perforated film having air permeability by peeling it if necessary. Therefore, it is possible to simplify the packaging of active substances such as desiccant, insect repellent, and oxygen scavenger as a double wrapping film, and if it is used as a lid material for a microwave oven heating packaging container, use only a perforated film during heating. Thus, it is possible to prevent spillage, and it is possible to improve the color reversion of raw meat when used as a lid material for a gas replacement packaging container for raw meat.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view showing an example of the laminated film according to the present invention. 1 ... perforated synthetic resin film 2 ... synthetic resin film 3 ... through hole 4 ... interface

Claims (1)

(57) [Claims] 1. A corona discharge comprising a perforated synthetic resin film (1) having a plurality of through holes (3) and a synthetic resin film (2) having no through holes, and at least one of the opposed film surfaces. An easily peelable laminated film which is obtained by laminating after treatment and has an adhesive strength of an interface (4) between the film (1) and the film (2) of 5 to 100 g / 20 mm width.