JPS5947665B2 - heat shrinkable laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-shrinkable laminated film, and more particularly to a laminated film that has a gloss suitable for packaging and decoration and can be wrinkled to an appropriate degree by heat-shrinking.

Currently, metal foils such as tin and aluminum are used to give wine bottle seals and packaging various containers, giving them a metallic luster and moderate wrinkles, but there are difficulties in processing wrinkles, so a new type of material is needed. is required.

The present invention provides a heat-shrinkable laminated film that has excellent metallic luster and can be easily wrinkled to an appropriate degree. A metal-deposited synthetic resin film (hereinafter referred to as metal-deposited film) having a heat-resistant temperature higher than the suitable shrinkage temperature of the heat-shrinkable film is attached on one side with a relatively weak bonding force that does not inhibit the shrinkage ability of the heat-shrinkable film. A heat-shrinkable laminated film (hereinafter referred to as a laminated film) that is laminated using a laminating agent that has
It is.

The laminated film of the present invention can be used at a temperature at which the heat-shrinkable film that is the base of the film can fully exhibit its shrinkage ability (hereinafter referred to as the "optimum shrinkage temperature"), and at which the metal-deposited layer of the metal-deposited film can be damaged or damaged due to shrinkage of the film. When heated below the temperature at which cracks occur, resulting in whitening and loss of gloss (hereinafter referred to as heat-resistant temperature), the heat-shrinkable film will shrink and, due to its shrinkage ability, the bonded surface may shift slightly (partial peeling). As a result, the other metal-deposited film becomes wrinkled without losing its luster, and the laminated film itself becomes wrinkled.

The reason why the laminated film of the present invention has such properties is that
For the heat-shrinkable film that is the basis of the laminated film, we use a film that exhibits a good shrinkage rate at relatively low temperatures, and (b) at the same time, the metal-deposited film has a heat-resistant temperature that is slightly higher than the appropriate shrinkage temperature for the heat-shrinkable film. Using a film, ←→ A laminating agent that has a relatively weak laminating force that does not inhibit the shrinkage ability of the heat shrinkable film is used for laminating the metallized film and the heat shrinkable film. I think there is.

One of the shrinkable films of the laminated film of the present invention has a relatively low suitable shrinkage temperature and a high shrinkage force (
It is preferable to use a material that exhibits a high shrinkage ability (high shrinkage ability) and causes displacement on the bonded surface.

Generally, a film obtained by uniaxially or biaxially stretching a synthetic resin such as polyvinyl chloride, polyethylene terephthalate, or polypropylene can be suitably used.

In addition, the metallized film has a higher heat resistance, or in other words, the metallized layer is damaged or cracked due to heat shrinkage, causing whitening and loss of luster. In this case, wrinkles with good metallic luster can appear, so this is preferable. This metal-deposited film may shrink slightly, but it is necessary to appropriately select the combination with the film that serves as the base of the laminated film and the conditions for shrinkage of the laminated film depending on its heat resistance temperature.

Examples of the metal-deposited film include films made of the above-mentioned synthetic resins and metals such as aluminum, tin, and silver deposited thereon.

Furthermore, as the laminating agent used for laminating the metallized film and the heat-shrinkable film, commonly used isocyanate adhesives and acrylic adhesives can be used; Taking this into consideration, it is preferable to use an adhesive that has a small collective force and is easily fluidized by heat, that is, an adhesive that exhibits sufficient adhesive strength at room temperature but whose adhesive strength decreases when heated.

Note that the metallized film may be laminated to the heat-shrinkable film on one side or both sides of the heat-shrinkable film, or on either the metallized side or the non-metallized side, but in order to obtain a product with a beautiful appearance. is preferably attached to a non-evaporated surface.

As mentioned above, the method for obtaining a laminated film of the present invention having a beautiful metallic luster and good wrinkles is generally carried out at a suitable shrinkage temperature for a heat-shrinkable film and below the heat-resistant temperature for a metallized film. Just heat it.

In other words, a heat-shrinkable film with a shrinkage rate of 40 to 60% at a suitable shrinkage temperature is bonded to a metal-deposited film with a heat-resistant temperature nearly twice that of the suitable shrinkage temperature, with a relatively weak bonding strength (for example, 300 to 500 f). When the laminated film of the present invention laminated with a width of /25-width) is heat-shrinked at a temperature above the suitable shrinkage temperature and below the heat-resistant temperature, the laminated film exhibits good wrinkles while retaining its original metallic luster.

However, even if this film is heated at a temperature below the optimum shrinkage temperature (for example, about 2/3 of the optimum shrinkage temperature), the heat-shrinkable film does not shrink sufficiently, and its shrinkage ability is inhibited by the metal-deposited film and the laminating agent, resulting in a laminated film. will only curl.
Furthermore, when this film is heated to a temperature higher than the heat-resistant temperature (for example, 10 to 20% higher than the heat-resistant temperature), the metal-deposited film will rapidly shrink, and the metal-deposited layer will break or crack. This results in whitening and loss of luster.

However, heating shrinkage of laminated films is not only the heating temperature but also the heating time.If the heating time is very short even when the temperature is higher than the heat-resistant temperature, good wrinkles can be achieved without losing the metallic luster. It can appear.

Therefore, heating conditions must be selected depending on the heat shrink film, metallized film, laminating agent, etc. used. As described above, when the laminated film of the present invention is heat-shrinked without using special equipment, the heat-shrinkable film shrinks, whereas the heat-resistant metal-deposited film hardly shrinks, so there is a shear stress between the two. The bonding agent, which has a weak bonding force, cannot withstand the shear stress and partially peels off, causing wrinkles in the peeled areas of the bonded metallized film, resulting in a beautiful metallic luster. and can easily make good wrinkles appear.

Moreover, since the shape is flat before heat shrinkage, it can be molded into any shape according to the application purpose, making it extremely excellent in practical use. Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Approximately 0.1 μm of aluminum was deposited on one side of a biaxially stretched polyethylene terephthalate (PET) film with a thickness of 12 μm by a vacuum deposition method to obtain a metal-deposited film.

The heat resistance temperature of this film is 200 to 220°C, and the shrinkage rate in the stretching direction at that time is 2.5 to 6%. A uniaxially stretched heat-shrinkable polyvinyl chloride (PVC-S) film with a thickness of 70μ is laminated on the non-evaporated surface of the film to form the laminated film of the present invention (
A PET/PVC-S) film was obtained. This PVC-S
The shrinkage force of the film is 40 kg/1, and the temperature at which the shrinkage rate in the stretching direction is 50% is 95 to 100°C. The lamination was carried out by a dry lamination method using an isocyanate adhesive. Bonding strength is approximately 490f/25-
It is the width. When this PET/PVC-S film was heat-shrinked at a temperature of 200°C for 2 minutes, the film shown in Table 1 retained its original aluminum luster.
Furthermore, the appearance of the PVC-S film was extremely good, with small wrinkles appearing in the direction perpendicular to the stretching direction (hereinafter referred to as the v direction). However, even when this film was heated for 2 minutes at a temperature of 60 to 80°C, it only curled slightly and no wrinkles appeared.

When this film was heated for 5 minutes at a temperature of around 240°C, it turned white and lost its metallic luster;
When heated for 0 seconds, wrinkles appeared without losing the metallic luster.

Example 2 A PVC-S film as a heat-shrinkable film, which was also used in Example 1, was laminated to the non-vapor-deposited surface of the PET film, which was used in Example 1 as a metallized film, to form a laminated film (PET/PVC-S) of the present invention. ) got the film.

They were laminated using an acrylic adhesive, and the lamination strength was approximately 500 r/25 mm width. This PET/PVC-
When the S film was heat-shrinked at a temperature of 200°C for 2 minutes, the film retained its original aluminum luster as shown in Table 1, and also had wide wrinkles in the V direction, giving it an extremely good appearance. It was hot.

Example 3 Approximately 0.1 μm of aluminum was deposited on one side of a biaxially stretched polypropylene (PP) film with a thickness of 20 μm by a vacuum deposition method to obtain a metal-deposited film.

The heat resistance temperature of this film is 120 to 140°C, and the shrinkage rate at that time is 2.5 to 6%. The shrink film used in Example 1 was used on the non-evaporated surface of the film.
Lamination of the present invention by laminating S film (PP/PVC-S)
I got the film. As in Example 2, acrylic adhesive was used for lamination, and the lamination strength was approximately 3507/25wr1.
It is n width.

When this PP/PVC-S film was heat-shrinked at a temperature of 200°C for 2 minutes, as shown in Table 1, the film retained its original aluminum luster and had no width in the shrinking direction (V direction). The grains were exposed and the appearance was very good. Example 4 A biaxially stretched heat-shrinkable polyethylene terephthalate (PET-S) film with a thickness of 12 μm was laminated to the metal-deposited surface of the PP film used as the metal-deposited film used in Example 3 to form the laminated (PP) film of the present invention. /PET-S) film was obtained.

The shrinkage force of this PET-S film is 50 to 100K9/
Also, the temperature indicating 50% of the direction is 55 to 60°C.

As in Example 2, acrylic adhesive was used for lamination.

The bonding strength is approximately 300t/257m width. This PP
/PET-S film was heat-shrinked at 200°C for 2 minutes, and as shown in Table 1, the film retained its original aluminum luster. The appearance was extremely good, with numerous wrinkles present. Example 5 Example 4 was applied to the non-evaporated surface of the PET film used as the metal-deposited film used in Example 1.
A laminated (PET/PET-S) film of the present invention was obtained by laminating the PET-S film as the heat-shrinkable film used in .

As in Example 2, acrylic adhesive was used for lamination, and the lamination strength was approximately 480 f/25 Tm width. This P
When the ET/PET-S film was heat-shrinked at a temperature of 200°C for 2 minutes, as shown in Table 1, this film had an aluminum luster similar to that of Example 4. The wrinkles appeared and the appearance was very good.

Comparative Example Example 5 A comparative laminated film (P
ET/PET-S) film was obtained.

The bonding strength is 8507/251rr1n width or more.

(PET film was cut and measurement was not possible) This PET film for comparison
/PET-S film at 200°C as in the above example.
When the film was heated and shrunk for 2 minutes, the original aluminum luster remained, but the entire film curled and no wrinkles appeared.

Claims (1)

[Claims] 1. A metal vapor-deposited synthetic resin film having a heat-resistant temperature higher than the suitable shrinkage temperature of the heat-shrinkable synthetic resin film is placed on at least one side of the heat-shrinkable synthetic resin film to inhibit the shrinkage ability of the heat-shrinkable synthetic resin film. A heat-shrinkable laminated film that is bonded using a bonding agent that has a relatively weak bonding force.