JPH0741699B2 - Heat-shrinkable sheet with a glittering pattern - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-shrinkable sheet having a glittering pattern formed by laminating heat-shrinkable films on both front and back surfaces of a metal thin film.

[Conventional technology]

As the heat-shrinkable sheet having a glittering property, a heat-shrinkable film coated with a paint having a glittering property, a heat-shrinkable film coated with a hard resin having excellent metal vapor deposition characteristics, and then subjected to a metal vapor deposition treatment, It is known that a heat-shrinkable film is laminated with a metal foil or a vapor-deposited film that does not change even at the temperature during the shrinking treatment, but in the case of, the brightness is poor.
In the cases of and, there is a problem that a uniform surface condition cannot be obtained unless the shrinkage rate at the time of heat shrinkage is controlled to 3% or less, which is difficult to put into practical use for mechanical loading such as a bottle cap cover. there were.

Therefore, the present inventor has diligently studied to obtain a heat-shrinkable sheet excellent in brilliance which can be effectively used for mechanical loading such as a cover of a bottle cap by improving such a defect. A thin metal film is provided on one side of a flexible film via an adhesive layer with a very high degree of elongation, and a non-heat-shrinkable resin layer with a very low degree of elongation is then sequentially laminated on it. By doing so, it was found that a heat-shrinkable sheet having an appearance excellent in brilliance can be obtained even when heat-shrinked by 10% or more, and a patent application was previously filed (JP-A-63-37931).

[Problems to be Solved by the Invention]

However, the heat-shrinkable sheet of the patent application has excellent glitter even when heat-shrinked by 10% or more, but high shrinkage causes foil dust, and therefore cannot be applied to packaging of bottle mouths that come into direct contact with food, etc. However, since a directional crack was generated, it was easy to obtain a productless appearance. The metallic luster produced by the metallic thin film at this time has a poor design effect because it shines evenly over the entire surface of the sheet, and the matte state of the metallic luster can be changed in various ways, and characters and figures are displayed on the film. It did not have a function to do. In addition, when it is used in a tubular shape when it is highly shrunk, it is necessary to overlap and join both ends of the heat-shrinkable sheet. However, in this joining, that is, "back sticking process", when a solvent is used, the adhesive layer The heat-shrinkable sheet is difficult to be directly joined to each other because the heat-shrinkable sheet is easily peeled off and the heat-shrinkable sheet is newly overlapped and joined, which requires special processing.

Therefore, the present invention has a metallic luster, does not cause foil dust even when highly shrunk, and can present a pattern such as letters or figures due to the difference in the contrast of the metallic luster during shrinking, An object of the present invention is to provide a heat-shrinkable sheet which has an excellent appearance and is capable of performing back-adhesion processing with good workability.

[Means for Solving the Problems]

The heat-shrinkable sheet exhibiting a glittering pattern of the present invention,
A heat-shrinkable film is provided on both front and back surfaces of a metal thin film via an adhesive layer, wherein a first adhesive layer on the front surface side and a second adhesive layer on the back surface side of the adhesive layer are provided. The difference in dry film elongation of 200% or more, and the dry film elongation of the first adhesive layer is 200% or more, and the first adhesive layer is coated on the entire surface, On the other hand, the second adhesive layer is characterized in that it is coated in a pattern (note that the dry film elongation in the present invention indicates the value measured by JIS K-7113).

That is, in the present invention, the second adhesive layer on the back surface side of the metal thin film is adhered in a pattern to the heat shrinkable film on the back surface side, and the adhesive layer provided on both front and back surfaces of the metal thin film. Since the dry film elongation of is different, the wrinkles and cracks generated in the metal thin film when heat-shrinking are different between the part where the second adhesive layer is present and the part where the second adhesive layer is not present,
As a result, a glittering pattern can be exhibited.

Further, in the portion of the metal thin film adhered by both the adhesive layers of the first adhesive layer and the second adhesive layer, shrinkage stress from both heat shrinkable films is received at the time of heat shrinkage. In the part of the metal thin film that is bonded only by layers,
Since only the shrinkage stress from the heat shrinkable film on the surface side is received during heat shrinkage, the magnitude of the shrinkage stress acting on each metal thin film part is different, and the difference between this shrinkage stress and the difference in dry film elongation described above is Due to the synergistic effect, it is possible to obtain a clear pattern having a difference in glitter on the metal thin film.

The heat shrinkable film that can be used in the present invention,
It is preferable to use a film having a heat shrinkability of 10% or more, and any of the films generally commercially available as a heat shrink film can be applied. Examples of typical materials include polyvinyl chloride, polyethylene, polypropylene and polyester.

The heat-shrinkable film may have different thicknesses on the front and back sides of the metal thin film, or may have the same thickness, but was prepared using heat-shrinkable films having different thicknesses. When a heat-shrinkable sheet is actually loaded into a bottle or the like for heat-shrinking, bringing a thick heat-shrinkable film to the side that receives the heat strongly causes strong heat shrinkage, shortening the shrinking time and making the appearance tighter. Can be finished.

Next, regarding the adhesive layer of the present invention, the difference in dry film elongation between the first adhesive layer on the front surface side and the second adhesive layer on the back surface side is 20
It is sufficient that the first adhesive layer has a dry film elongation of 200% or more, and is generally 200% or more.
It is formed using acrylic resin adhesives, urethane and other rubber adhesives, vinyl chloride / vinyl acetate copolymer adhesives, etc., which have a dry film elongation of about 1000%.
It may be formed using a so-called adhesive.

In the present invention, it is particularly preferable that the dry adhesivenesses of the first adhesive layer and the second adhesive layer are both 200% or more, and the difference between the dry adhesivenesses of the two is 400% or more, In this case, a pattern having particularly excellent glitter is exhibited. Furthermore, the dry film elongation of at least one of the first adhesive layer and the second adhesive layer is preferably 600% or more.

In the present invention, the dry film elongation of the first adhesive layer coated on the entire surface is the
If it is larger than that of the adhesive layer, the appearance of the pattern portion that is not partially adhered by the second adhesive layer after heat shrinkage will be excellent in brilliance, and conversely, the dry film extension of the first adhesive layer will be achieved. If the degree is less than that of the second adhesive layer, the second
The appearance after heat shrinkage of the pattern portion partially adhered by the adhesive layer has excellent glitter.

Further, the metal thin film of the present invention may be composed of any of aluminum, chromium, nickel, silver, tin and other metals or alloys, and the formation method thereof is not particularly limited. Generally, it can be formed by vacuum vapor deposition, sputtering, ion plating or the like.

In the present invention, it is preferable to directly provide a heat-shrinkable film on both front and back surfaces of the metal thin film via a predetermined adhesive layer, but when it is manufactured by a transfer method or the like, it is generally applied at the time of forming a transfer foil. The adhesive layer may be applied to a metal thin film having a protective layer or the like.

The method for producing the sheet of the present invention is also not particularly limited, but for example, one side of the heat-shrinkable film, a support / release layer / protection via a first adhesive layer having a dry film elongation of 200% or more. Layer / metal vapor deposition layer and the like, and then the support of the transfer foil is peeled off, and then the peeled surface has a difference in dry film elongation of 200% or more from the first adhesive layer. Two
It can be manufactured by a method such as bonding a heat-shrinkable film via an adhesive layer.

Since the sheet of the present invention has both the front and back surfaces of the metal thin film covered with the heat-shrinkable film, the metal thin film is not peeled off to cause foil dust even when highly shrunk, and is stable for any application. Can be used. Furthermore, since the back and back processing is made of a film having good processability on both front and back surfaces, strong processing can be easily performed by general processing without delamination. Since both surfaces of the metal thin film are covered with the heat-shrinkable film having an appropriate elongation, the metal thin film can shrink uniformly according to the shrinkage of the heat-shrinkable film.

〔Example〕

Production Example 1 A transfer foil having a 1 μm-thick acrylic-urethane protective layer and a 400 to 500 Å Al vapor-deposited layer formed by gravure coating on one side of a polyester film # 25 was prepared. The first adhesive layer having a dry film elongation of 880% and a thickness of 3 to 5 μm (Takelac A-310, a polyurethane adhesive manufactured by Takeda Pharmaceutical Co., Ltd.)
And Takeda Pharmaceutical Industry Co., Ltd. isocyanate hardener “Takenate A-3” in a ratio of 12/1).
A 30 μm heat-shrinkable polyvinyl chloride film was laminated.

Next, the polyester film was peeled off, and the acrylic adhesive having a thickness of 2 to 5 μm was further used as a second adhesive layer on the peeling surface side of the resulting silver-colored beautiful metallic gloss film (Nippon Synthetic Chemical Industry Co., Ltd. ) Coponile # 8020, dry film elongation = ∞) coated in a grid pattern, and after drying,
A heat-shrinkable vinyl chloride film with a thickness of 30 μm, which has the same heat-shrinkage direction as the polyvinyl chloride film used previously, is attached, and a heat-shrinkable film is provided on both sides of the Al vapor deposition layer, giving it a beautiful silver metallic luster. A heat shrinkable sheet was prepared.

Production Examples 2 to 12 Production Example 1 except that the adhesive compositions shown in Table 1 below were used as the first adhesive layer and the second adhesive layer of Production Example 1.
A heat-shrinkable sheet having a beautiful silver metallic luster was prepared in the same manner as in.

The composition ratio of the adhesive layer in each production example described in Table 1 is the combination of the dry film elongation (elongation rate) of the first adhesive layer and the second adhesive layer as shown in Table 2. Which was selected to obtain Takelac A-
315, A-975, A-2071 are all Takeda Pharmaceutical Co., Ltd.
Takenate A-50, a polyurethane adhesive manufactured by Takeda Pharmaceutical Co., Ltd., is an isocyanate curing agent.

Example of use The twelve kinds of heat-shrinkable sheets obtained in the above Production Examples 1 to 12 are formed into a tubular shape by back-adhesion processing with the first adhesive layer on the inside and the second adhesive layer on the outside. Form it, cut it to an appropriate length and load it into the cap of one bin, and
Heat treatment was performed so that the amount became 25%, and the beauty effect due to the difference in glitter was evaluated. The result is the first adhesive layer and the second adhesive layer.
It is shown in Table 2 together with the elongation percentage of the adhesive layer. In Table 2, Production Examples 2, 10, 11 and 12 are comparative examples.

As is clear from the results of Table 2, the dry film elongation of the first adhesive layer is 200% or more, and the difference in dry film elongation between the first adhesive layer and the second adhesive layer is When it is 200% or more, a glittering pattern is obtained (see Production Examples 1 and 3 to 9), and particularly when the dry film elongations of the first adhesive layer and the second adhesive layer are both 200% or more. When the difference between the dry film elongations of both is 400% or more, the difference in glittering property was remarkable, and a very clear pattern rich in glittering property was obtained (Production Example 1, 4 and 5).

From Production Example 11, even if the difference in the dry film elongation is 400% or more, when the adhesive of 200% or less is used for the first adhesive layer, the adhesive layer is hard, so It was found that the brilliance was lost due to stress fracture and a clear pattern could not be obtained.

On the other hand, Comparative Examples in which the difference in dry film elongation between the first adhesive layer and the second adhesive layer is 200% or less (Production Examples 2, 10 and 12)
In contrast, the difference in glitter was small and a clear pattern could not be obtained.

When the dry film elongation of the first adhesive layer is smaller than that of the second adhesive layer (Production Examples 1, 7 and 9), the second adhesive layer
In the case where the portion where the adhesive layer is present exhibits glitter, while the dry film elongation of the first adhesive layer is larger than that of the second adhesive layer (Production Examples 3 to 6 and 8), The portion where the second adhesive layer did not exist showed glitter.

From the above results, in the heat-shrinkable sheet of the present invention, the dry film elongation of the first adhesive layer is 200% or more, and
The difference in dry film elongation between the first adhesive layer and the second adhesive layer is 20
It is necessary to be 0% or more, and especially the dry film elongations of the first adhesive layer and the second adhesive layer are both 200% or more, and the difference in dry film elongation between the two is 400% or more. It turns out that it is preferable.

The heat-shrinkable sheet of the present invention was also excellent in workability in spine sticking using a simple solvent.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The heat-shrinkable sheet of the present invention has a metallic luster, and when heat-shrinking, a difference in the glittering property is produced depending on the presence or absence of the second adhesive layer, and a pattern with strong contrast such as characters and figures is obtained. You can Therefore, the heat-shrinkable sheet of the present invention can be a product excellent in distinctive design effect due to heat shrinkage. For example, in addition to a sealant for a bottle cap of wine, cosmetics, drinking water, etc. It can be used stably and effectively as a strip-shaped label for bottles or canned foods.

The heat-shrinkable sheet of the present invention can be back-bonded with good workability without causing foil dust even when highly shrunk.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // B29K 105: 02 B29L 9:00

Claims (2)

[Claims] 1. A heat-shrinkable film provided on both front and back surfaces of a metal thin film via an adhesive layer, wherein the first adhesive layer on the front surface side and the first adhesive layer on the back surface side of the adhesive layer. 2 The difference in the dry film elongation from the adhesive layer is 200% or more, and the dry film elongation of the first adhesive layer is 200% or more, and the first adhesive layer is formed on the entire surface. A heat-shrinkable sheet having a glittering pattern, which is coated, while the second adhesive layer is coated in a pattern. 2. The dry film elongations of the first adhesive layer and the second adhesive layer are both 200% or more, and the difference in dry film elongation between the two is 400% or more. The heat-shrinkable sheet according to claim 1.