JPS5936585B2 - Rust-proof skin packaging film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rust-proof skin packaging film, and in particular, in skin packaging for metal products, the film has excellent thermal adhesion to a mount and a long-lasting rust-preventing effect on metal products. An object of the present invention is to provide a skin packaging film that has the same characteristics as the skin packaging film.

Conventionally, anti-rust films have a low gas permeability coefficient (hereinafter referred to as air impermeability).

) A laminated film consisting of an outer film and an inner resin layer with greater air permeability than the film, with a volatile rust preventive agent mixed and dispersed or interposed within the air permeable resin layer or between the layer and the outer film. Rust-resistant laminated film is known, and is also known as skin packaging, in which a thermoplastic film is placed on the packaged item placed on a mount, and the film is heated and vacuumed to thermally bond it to the mount. Ethylene-vinyl acetate copolymer (hereinafter referred to as ethylene-vinyl acetate copolymer It has been proposed to use a film called EVA resin. However, when using the former rust-proof laminated film for skin packaging,
The air-permeable resin used has problems with thermal adhesion to the mount, and when EVA resin is used, there are drawbacks such as rust often forming on the packaged metal products.

The inventor has conducted extensive research into eliminating these drawbacks, and
We have previously discovered that the above-mentioned drawbacks and other problems can be improved by using a copolymer of ethylene and alkyl acrylate having 1 to 4 carbon atoms (hereinafter referred to as EAA resin) in place of the above-mentioned EVA resin as a skin packaging film. However, in the above-mentioned rust-proof laminated plastic film, an impermeable film is used for the outer film, and the above-mentioned EAA resin film with high gas permeability is used for the inner film in contact with the mount and the packaged object. A vaporizable rust preventive agent layer is interposed or dispersed between both films or within the inner film, and the vaporizable rust preventive agent is applied to the metal product encapsulated through the highly air permeable inner film. The present invention was developed based on the realization that rusting of packaged metal products can be prevented for a long period of time. That is, the present invention provides a laminated film consisting of an outer plastic film with a small gas permeability coefficient and an inner plastic film with higher air permeability than the outer plastic film, and a vaporizable rust preventive layer in the inner film and/or between this and the outer film. A rust-preventive laminated film prepared by mixing and dispersing or interposing an agent, characterized in that an ethylene/Obi-1 alkyl acrylate copolymer is used as the inner film, and the inner surface thereof is subjected to a corona discharge treatment. The main purpose of this paper is to provide a rust-proof skin packaging film.

As mentioned above, the present invention requires the use of EAA resin as the air-permeable resin, and the inner film using this resin is required to have greater gas permeability than the air-impermeable outer film. As a result, the volatile rust preventive agent passes through the inner film and contributes to the rust prevention effect of the packaged product, while the outer film prevents the rust preventive agent from permeating and escaping into the atmosphere from the outside. can do.

Moreover, in the present invention, even if the inner film does not have a very high air permeability, the gas permeability of the film can be adjusted to a desired level by pre-drilling countless micropores on the entire surface of the film. It is also easy to do. Therefore, the EAA resin film used in the present invention has excellent thermal adhesion and transparency, and has particularly suitable performance as a skin packaging film.
This produces excellent effects when used. Next, as the outer film with a small gas permeability coefficient used in the present invention, commonly used polyethylene,
In addition to polypropylene, films made of polyester, nylon, polyvinyl chloride, etc. are suitable, and this helps prevent the volatile rust inhibitor from escaping to the outside, and the product of the present invention is desired for skin packaging. It plays a major role in maintaining strength and other physical properties. The volatile rust inhibitors used in the present invention are known ones, and representative ones include:
Synchronohexylammonium nitride is an example, but from among other known agents, those that do not adversely affect the resin components that make up the film and do not impair the adhesion of the films to each other and to the backing paper are selected and used. can do.

In the present invention, in addition to interposing a volatile rust preventive agent in a layer between the outer film and the inner film and bonding both films together by well-known lamination or dry lamination, The agent may be added to and mixed with the resin in advance to form the inner film, and then laminated with the outer bait film. The agent can also be interposed in a layered manner. Furthermore, in the present invention, it is effective to subject the surface of the air-permeable inner EAA resin film to a corona discharge treatment in order to further improve thermal adhesion to the mount.

The present invention will be explained in more detail below with reference to the drawings.

The same reference numerals in each figure indicate the same parts. FIG. 1 is a partially cutaway enlarged sectional view of a film showing an embodiment of the rust-proof skin packaging film of the present invention, in which 1 indicates, for example, a low-density polyethylene or polypropylene film, and 2
3 indicates a layer of a vaporizable rust preventive material applied to the film (the amount of rust preventive applied is preferably 5 g/a or more), and 3 represents EEA.
A resin film is shown.

The films 1 and 3 are laminated together with a vaporizable rust preventive layer 2 interposed therebetween, and the surface of the film 3 has an adhesive layer 4 subjected to corona discharge treatment. 2 and 3 show other embodiments of the present invention, FIG. 2 is a partially cutaway enlarged perspective view, and FIG. 3 is a partially cutaway enlarged view taken along the E-I line of the figure. shows a cross-sectional view,
The difference between this film and the one shown in Fig. 1 is that the inner film 3 in Fig. 1 has numerous holes 5, which allow the vaporization and permeation of the volatile rust preventive agent. The hole diameter (for example, 1 to 511 diameter) and the number (for example, 1 to 511 diameter) and the number (
For example, 100~20/100C! By appropriately selecting It), there is an advantage that a film having a desired gas permeability can be obtained.

There are no particular restrictions on the method of perforation, and in addition to the usual punching method, passing the film over a needle roll may also be used. Further, FIG. 4 shows another embodiment of the present invention, and is a partially cutaway enlarged sectional view of the film according to the present invention, in which the volatile rust preventive agent 2 is dispersed and included in the inner film 3. This is an example of the case.

Furthermore, in the rust-proof skin packaging film of the present invention shown in FIG. A layer 2 of a vaporizable rust preventive agent is interposed between the outer and inner films as shown in FIG. A rust preventive layer 2 may also be provided.

An example of the method for manufacturing a rust-proof skin packaging film according to the present invention is to manufacture a polyethylene or polypropylene film, and coat one side with a volatile rust preventive such as synchrohexyl ammonium nitride as an active ingredient. (manufactured by Mitsubishi Gas Chemical Industries, Ltd.).

Next, an EAA resin film is laminated with the coated side facing inside, and at the same time or after that, the surface of the EAA resin film is subjected to a well-known corona discharge treatment.
A product of the present invention as shown in FIG. 1 is obtained. Next, the results of testing the Examples of the present invention obtained as described above together with Comparative Examples will be shown. As is clear from the above results, it is recognized that the laminated skin packaging film using EVA resin without a vaporizable rust preventive agent rusts, whereas polyethylene film and EAA with a vaporizable rust preventive layer In the case of a resin film or a film in which numerous micropores are perforated, the adhesion to the mount is good, and no rust is observed. When there is a volatile anti-corrosion layer on the adhesive surface with the backing paper, rust does not occur on the iron pieces of the packaged item, but the adhesive strength between the film and the backing paper is extremely weak, making it difficult to achieve the original purpose of skin packaging. It is recognized that this is not possible. Thus, according to the present invention, it is possible to provide a rust-proof skin packaging film that is excellent in preventing rust from forming on metal products to be packaged over a long period of time without impairing the adhesive strength with the backing paper.

[Brief explanation of the drawing]

Each of the drawings shows each embodiment of the rust-proof skin packaging film according to the present invention as a partially cutaway enlarged view.
FIG. 1 is a sectional view, FIG. 2 is a perspective view, FIG. 3 is a sectional view taken along the E-I line in FIG. 2, and FIG. 4 is a sectional view according to another embodiment. is an outer plastic film with a small gas permeability coefficient, 2 is a volatile rust preventive agent, and 3 is a
4 is the inner EAA resin film in contact with the mount having high gas permeability; 4 is the adhesive layer portion on the surface of the inner film that has been subjected to corona discharge treatment to impart adhesion to the mount; and 5
3 shows countless micropores formed on the entire surface of the inner film of No. 3.

Claims (1)

[Claims] 1 Inside the inner film of a laminated film consisting of an outer plastic film with a small gas permeability coefficient and an inner plastic film with higher air permeability than the film, and/or
Or, in a rust-proof laminated film in which a volatile rust-preventive agent is mixed and dispersed or interposed between this and an outer film, an ethylene/C_1-_4 alkyl acrylate copolymer is used as the inner film, and the A rust-proof skin packaging film characterized by corona discharge treatment on the inner surface.