JP6715623B2 - Heat shrinkable film laminate - Google Patents

Description

The present invention relates to a heat-shrinkable film laminate in which one heat-shrinkable film and the other heat-shrinkable film are laminated via an adhesive. In particular, the present invention relates to a heat-shrinkable film laminate suitable for use in overlapping packaging of gifts and the like stored in a cosmetic box.

Heat-shrinkable films are often used when packaging products such as foods, confectionery, books, cosmetics, and pharmaceuticals. When using a heat-shrinkable film to wrap the product in an overlapped manner, cover the product with the film while appropriately cutting the heat-shrinkable film, heat-seal or melt-seal the edge of the film, and then heat the film. Contract. At this time, if the surface to be sealed is printed, sufficient sealing strength cannot be exhibited. Therefore, when printing is performed on the heat-shrinkable film, in order to ensure a sufficient sealing strength, printing is usually performed except for a place where heat sealing or fusing sealing is performed. However, in the overlappingly wrapped package, the fact that the seal portion is not printed greatly impairs the aesthetics.

When using heat-shrinkable film with the entire surface of the film printed in an overwrap packaging, if the product is wrapped with the heat-shrinkable film with the printing surface outside (the side not in contact with the product), the seal strength will decrease due to printing. Can be prevented. However, when this method is used, there are problems that ink adheres to the seal bar and that the film is rubbed during transportation and the print is peeled off.

Patent Document 1 is an invention for the purpose of providing a package in which the overlap-sealing portion of the overlapping-wrapped package has a small amount of transparent portions and its transparent portion and the sealing strength of the seal-sealing portion is sufficient. Patent Document 1 proposes to perform dot printing on the portion of the overlapping packaging that is sealed together.
However, in the film used for the packaging, since the part to be sealed with a palm is specified in advance, it is necessary to change the film when the size of the product changes. Further, the packaging body is not one in which printing is performed on the entire surface of the seal-sealed portion. Only the dot-like printing is applied to the seal portion, and the transparent portion is left in order not to reduce the seal strength.

2. Description of the Related Art In recent years, gifts and the like stored in a cosmetic box are often packaged with a printed plastic film instead of wrapping paper for the purpose of mechanizing packaging work, reducing packaging materials, and the like. In such applications, the designability of the package is emphasized, and therefore there is a demand for a heat-shrinkable film that can be overwrapped and that has the entire surface printed.

Patent Document 2 aims to provide a heat-shrinkable film laminate (laminate shrink film) capable of performing printing even on a heat-sealed portion and improving the appearance and function of a packaged product. It is an invention. In Patent Document 2, a heat-shrinkable film laminate in which one heat-shrinkable film (shrink film) and the other heat-shrinkable film are bonded together with an adhesive, and one heat-shrinkable film is the other A heat-shrinkable film laminate has been proposed in which a print layer containing a chlorinated polypropylene resin is formed on the surface on the heat-shrinkable film side. Since the print layer of the film is formed between the heat-shrinkable films, it is possible to print the heat-sealed portion.

JP, 2010-184740, A JP, 2014-121821, A

However, when a product is overlap-wrapped using the heat-shrinkable film laminate described in Patent Document 2, a part of the heat-shrinkable film laminate may be delaminated (peeled).

The present invention is a heat-shrinkable film laminate capable of performing printing up to a heat-sealed portion and improving the appearance and function of a packaged product without delamination after packaging. It is intended to provide a heat-shrinkable film laminate.

According to the present invention, as a means for solving the above problems, in a heat-shrinkable film laminate in which one heat-shrinkable film and the other heat-shrinkable film are laminated, the one heat-shrinkable film and the other The heat-shrinkable film is provided with a print layer, and the heat-shrinkable film laminate is characterized in that the print layers are laminated so as to face each other with an adhesive layer in between.
In addition, the heat-shrinkable film laminate characterized in that the print layer of the one heat-shrinkable film and the print layer of the other heat-shrinkable film are formed of the same resin component ink. Provided.
Further, the heat shrinkable film laminate is provided in which the resin component is a chlorinated polyolefin.
Further, the heat shrinkable film laminate is provided, wherein the adhesive is a polyether urethane adhesive.
Further, there is provided the heat-shrinkable film laminate, wherein the print layer included in the one heat-shrinkable film or the print layer included in the other heat-shrinkable film does not contain a color material.

In the heat-shrinkable film laminate described in Patent Document 2, one heat-shrinkable film and the other heat-shrinkable film have a print layer provided in one film and an adhesive layer applied to the other film interposed therebetween. In the heat-shrinkable film laminate of the present invention, one heat-shrinkable film and the other heat-shrinkable film are applied to the print layer applied to one film and the other film. The printed layer and the adhesive layer formed between the two printed layers are laminated. The reason why delamination is improved by increasing the number of printing layers is not clear, but it is not because the heat shrinkage property of one heat shrinkable film and the heat shrinkage property of the other heat shrinkable film become the same. I guess. Further, the adhesive layer present between the two heat-shrinkable films also seems to work in the direction of eliminating the difference in heat-shrinkage characteristics of each film, and contributes to the improvement of delamination.

According to the present invention, one heat-shrinkable film and the other heat-shrinkable film both have a print layer, and the print layers are adhered to each other by an adhesive layer. It is difficult for the body to delaminate. Further, since the two printing layers are provided, complicated printing becomes possible, and the heat-shrinkable film laminate can be provided with new functions such as design and light-shielding properties. Furthermore, since the entire surface of the heat-shrinkable film laminate has heat-sealing properties, even if the size of the product changes, the same heat-shrinkable film laminate can be used for overlapping packaging.

1 is a schematic cross-sectional explanatory view showing an example of the heat-shrinkable film laminate of the present invention.

Hereinafter, the present invention will be described in more detail, but the present invention is not limited thereto.
FIG. 1 is a schematic cross-sectional explanatory view showing an example of the heat-shrinkable film laminate 1 of the present invention. The heat-shrinkable film laminate 1 of the present invention comprises a heat-shrinkable film 2a composed of a heat-shrinkable film base 20a and a printing layer 21a, and a heat-shrinkable film composed of a heat-shrinkable film base 20b and a printing layer 21b. The shrinkable film 2b is laminated via the adhesive layer 3 so that the printing layers 21a and 21b face each other.

[Heat-shrinkable film]
The heat-shrinkable films 2a and 2b used in the present invention are composed of heat-shrinkable film substrates 20a and 20b and printed layers 21a and 21b, respectively.
<Heat-shrinkable film substrate>
The heat-shrinkable film base materials 20a and 20b can be molded from the resin conventionally used for heat-shrinkable films. For example, one selected from ester resins such as polyethylene terephthalate and polybutylene terephthalate, amide resins such as 6 nylon and 6,6 nylon, styrene resins such as polystyrene, and thermoplastic resins such as olefin resins such as polyethylene and polypropylene 1 It can be molded from one kind or two or more kinds of resins.

When the heat-shrinkable film laminate according to the present invention is used for packaging gifts stored in a cosmetic box (hereinafter, abbreviated as gift wrapping application), heat-shrinkable film base materials 20a, 20b are formed. As the resin to be used, it is desirable to use an olefin resin such as an ethylene resin or a propylene resin, or a laminated body of these. Since the heat-shrinkable film made of an olefin resin, particularly a propylene resin, has excellent surface gloss, the obtained package can have a high-grade feeling. As the ethylene-based resin, low density polyethylene, high-density polyethylene, ethylene-α-olefin copolymer and the like, and as the propylene-based resin, polypropylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene block copolymer and the like. However, it is particularly desirable to provide at least one layer of a propylene-ethylene random copolymer that can be stably stretched at a low temperature.

The method for producing the heat-shrinkable film base materials 20a, 20b from the above-mentioned thermoplastic resin is not particularly limited, and for example, the resin described above is formed into a film by an inflation extrusion molding method, a T-die extrusion molding method, or the like, and May be stretched using a tubular stretching method, a tenter stretching method, or the like. A heat-shrinkable film having a multilayer structure obtained by stretching a film having a multi-layer structure in which a plurality of the above-mentioned resins are formed by a co-extrusion method may be used as the heat-shrinkable film base materials 20a and 20b of the present invention.

A commercially available heat-shrinkable film can also be used as the heat-shrinkable film base materials 20a and 20b of the present invention. For example, a polypropylene heat-shrinkable film "OKUWRAP (registered trademark)" manufactured by Okura Industry Co., Ltd., a polyolefin multilayer shrink film "Lappler (registered trademark) 501", "Randy Five (registered trademark) NP300", or the like may be used. good.

The thickness of the heat-shrinkable film base material is not particularly limited and can be appropriately designed depending on the application to be used, but if the film thickness is too thin, the film-forming property decreases, and if it becomes too thick, it is uniform. Since it is difficult to stretch the film to 5 to 30 μm, it is particularly preferably about 7 to 20 μm. For gift wrapping purposes, the heat-shrinkable film preferably has a thickness of 5 to 20 μm, particularly 7 to 12 μm. If the film thickness is too thin, the film may be broken or distorted when the gift is transported, and if the film thickness is too thick, the packaging finish will be poor.
The heat shrinkage rate of the heat shrinkable film base material can also be appropriately designed according to the application used, but in the case of gift packaging applications, the MD (film length direction) shrinkage rate and the TD (width direction) shrinkage rate. Is preferably about the same.

It is preferable that the heat-shrinkable film base materials 20a and 20b have similar heat-shrinkage characteristics in order to prevent delamination. Therefore, it is preferable to use the same kind of resin (the same kind at the level of propylene resin and ethylene resin), and it is particularly preferable to use the same resin. Further, the film thickness of one heat-shrinkable film base material 20a is 0.8 to 1.2 times, further 0.9 to 1.1 times, that of the other heat-shrinkable film base material 20b. It is preferably 0.95 to 1.05 times.

The heat-shrinkable film base material 20a on one side and the heat-shrinkable film base material 20b on the other side may be films made of different resins as long as they have similar heat-shrinkable properties. One of the heat-shrinkable film base materials 20a is molded from an ester-based resin or an amide-based resin, and the other heat-shrinkable film base material 20b is molded from a resin that can be heat-sealed at a low temperature such as an olefin-based resin. The obtained heat-shrinkable film laminate can be heat-sealed by a seal bar.

[Print layer]
The print layers 21a and 21b can be formed from the ink conventionally used for printing a plastic film, but in view of printability, it is preferable to use an ink for gravure printing. As the resin used in the ink for gravure printing, vinyl chloride resin, chlorinated rubber, chlorinated polyolefin, acrylic resin, amide resin, urethane resin, nitrified cotton resin, etc. are known. It is desirable that 21a and the printed layer 21b contain the same resin component. When the same resin component is contained, the heat shrinkable properties of one heat shrinkable film 2a and the other heat shrinkable film 2b can be approximated.

The printed layers 21a and 21b of the present invention preferably contain a chlorinated polyolefin as a resin component, and particularly preferably a chlorinated polypropylene. Since the print layer using chlorinated polyolefin is relatively soft, it is possible to improve delamination due to the difference in heat shrinkage characteristics of the heat shrinkable film base materials 20a and 20b. When the heat-shrinkable film base materials 20a and 20b are subjected to corona discharge treatment, the fusing seal strength may decrease, but the chlorinated polyolefin is a heat-shrinkable film base material that is not subjected to corona discharge treatment. Excellent adhesion to 20a and 20b.

The thickness of the print layers 21a and 21b is not particularly limited, but the general thickness (after drying) is about 0.1 to 5 μm. In order to prevent delamination of the heat-shrinkable film laminate 1, it is desirable that the print layers 21a and 21b have the same thickness. Specifically, the film thickness of one printing layer 21a is 0.8 to 1.2 times, further 0.9 to 1.1 times, and further 0.95 to 1.05 times the film thickness of the other printing layer 21b. It is desirable to be double.

Since the printed layers 21a and 21b both contribute to the prevention of delamination of the heat-shrinkable film laminate 1, it is desirable that these cover the entire one-side surface of the heat-shrinkable film substrates 20a and 20b. It is desirable to cover at least 90% or more. When the heat-shrinkable film laminate 1 is viewed in a plan view, if there are many portions where the printing layers 21a and 21b do not exist, delamination may occur even if an adhesive layer described below is used.

Further, both of the print layers 21a and 21b may include a color material such as a pigment or a dye, but one of them may not include the color material. In other words, one print layer 21a (or 21b) can print a desired pattern on the film, and the other print layer 21b (or 21a) can print a colorless ink for the purpose of preventing delamination. is there. If the printing is performed only on one of the printing layers, the problem that the design shifts is unlikely to occur.
Of course, each of the printing layers 21a and 21b may be formed of an ink containing a color material. By providing two printing layers, it is possible to obtain a film excellent in design that has not been obtained in the past. In addition, when packaging the product, if you print the desired design or product name on the outer printing layer and perform solid printing of white, black, silver, brown, etc. on the product printing layer, heat shrinkage The film laminate can be made to have a light-shielding property. The solid printing may be performed by printing two layers or more. For example, a heat-shrinkable film on the product side (inner side) when packaging a product can be printed with a dark color such as black or brown, and further with a white print on the print layer.
When it is desired to prevent the product from being seen through, the heat-shrinkable film base material on the product side can be colored when the product is packaged.

[Adhesive layer]
For the adhesive layer 3, an adhesive conventionally used as an adhesive for dry lamination can be used. Adhesives for dry lamination include two-component curing type urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, epoxy adhesives, etc. However, in the present invention, it is preferable to use a urethane adhesive such as a two-component curing type urethane adhesive, a polyester urethane adhesive, or a polyether urethane adhesive, and especially a polyether urethane adhesive. It is desirable to use an agent. Since the urethane-based adhesive has excellent flexibility, the adhesive layer functions as a cushioning material even if the heat-shrinkable film 2a on one side and the heat-shrinkable film 2b on the other side have slightly different heat-shrinkable properties, and the heat-shrinkable property is improved. Delamination of the film laminate 1 is prevented.

[Method for producing heat-shrinkable film laminate]
The method for producing the heat-shrinkable film laminate according to the present invention will be described with reference to one example.
<Printing process>
First, printing is performed on one heat-shrinkable film base material 20a and the other heat-shrinkable film base material 20b. Prior to printing, the heat-shrinkable film base materials 20a and 20b may be subjected to corona discharge treatment. As a printing method, known printing methods such as gravure printing, flexo printing, screen printing, and dry offset printing can be adopted. However, using gravure printing enables high-speed printing.

<Lamination process>
Next, the two heat-shrinkable films 2a and 2b on which the print layer is formed are laminated. Prior to the lamination, the adhesive 3 is applied on the printed layer 21a of the one heat-shrinkable film 2a. The method of applying the adhesive is not particularly limited, but, for example, a gravure printing method can be adopted. The amount of the adhesive applied is preferably such that the solid content in the adhesive is about 0.1 to 5 g/m ² . The heat-shrinkable film coated with the adhesive is dried to some extent in a drying oven and then laminated with the other heat-shrinkable film 2b to form the heat-shrinkable film laminate of the present invention.

The effect of the heat-shrinkable film laminate of the present invention was confirmed by Examples and Comparative Examples.
[Example 1]
The polypropylene heat-shrinkable film "OKUWRAP (registered trademark)" manufactured by Okura Industry Co., Ltd. was printed on one surface with an ink containing chlorinated polypropylene as a resin component to obtain one heat-shrinkable film. .. The other heat-shrinkable film was also produced in the same manner.
Then, a polyerurethane-based resin adhesive is applied onto the printed layer of the one heat-shrinkable film, and after drying, the other heat-shrinkable film is placed on the adhesive layer, and the printed layer of the film is The heat-shrinkable film laminate of the present invention was obtained by laminating the adhesive layer in contact with the adhesive layer.

[Comparative Example 1]
A heat-shrinkable film laminate of Comparative Example 1 was produced in the same manner as in Example 1 except that the printing layer was not formed on the other heat-shrinkable film.

Using the heat-shrinkable film laminates of Example 1 and Comparative Example 1, a cosmetic box was overwrapped and the appearance of the overwrapped package was visually confirmed.
No delamination was confirmed in the package using the heat-shrinkable film laminate of Example 1. On the other hand, in the package of Comparative Example 1, one heat-shrinkable film and the other heat-shrinkable film were partially delaminated.

Since the heat-shrinkable film laminate of the present invention can print on almost the entire surface of the film, the package wrapped with the film has excellent design. Therefore, it is suitable to be used instead of the wrapping paper in the gift wrapping application where the wrapping paper has been conventionally used.
Of course, it can also be used for applications such as food products, confectionery, documents, medicines, etc., which have been conventionally packaged with a heat-shrinkable film, for overlapping packaging, sleeve packaging, and the like.

1 Heat Shrinkable Film Laminates 2a, 2b Heat Shrinkable Films 20a, 20b Heat Shrinkable Film Base Materials 21a, 21b Printing Layer 3 Adhesive Layer

Claims (2)

In a heat-shrinkable film laminate in which one heat-shrinkable film and the other heat-shrinkable film are laminated,
The one heat-shrinkable film and the other heat-shrinkable film both have a printing layer, and the printing layers are laminated so as to face each other via an adhesive layer ,
The print layer provided with the one heat-shrinkable film, and the print layer provided with the other heat-shrinkable film both contain chlorinated polypropylene,
The one heat-shrinkable film and the other heat-shrinkable film is a polyolefin heat-shrinkable film having a layer made of polypropylene resin on the printing layer side,
The heat-shrinkable film laminate, wherein the adhesive layer is a polyether urethane adhesive . The heat-shrinkable film laminate according to claim 1, wherein the one heat-shrinkable film and the other heat-shrinkable film have a thickness of 5 to 30 µm.