An overwrapping film wherein a plastic base film is coated with a plastic material to form an anchor coat layer, which is, in turn, further coated with ink to form an ink layer thereon, and a metal layer is then deposited on the ink layer through the process of vacuum evaporation. The plastic base film is thermally contracted to produce a tightly-packed configuration, while the evaporated metal layer furnishes a metallic gloss to a printed display pattern provided by the ink layer.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an overwrapping film using a plastic base film 
and a method of producing the same. 
2. Description of the Prior Art 
Tape cassettes commercially available for use in cassette tape recorders or 
the like are sold at stores and are typically packed with an overwrapping 
film which employs a plastic base film. In order to ensure easy visual 
distinction from other merchandise, the overwrapping film generally has a 
printed display region to show a trade name and other data which, for 
example, could represent the audio characteristics of the particular 
cassette. The overwrapping film for articles exhibited and sold in stores 
should be finished and in a satisfactory condition for enhancing the image 
of the merchandise contained therein since the appearance thereof usually 
exerts a great influence on the buyer. Typical materials adapted to 
produce overwrapping films for tape cassettes include transparent 
synthetic resins or plastics such as polypropylene. 
A display region is formed on each film by printing with a variety of 
paints so as to attain a favorable esthetic effect to the overall design. 
Furthermore, by utilizing the thermal contraction property of the plastic 
material, a tightly-packed configuration is obtained with the contraction 
of the overwrapping film subsequent to packing. 
In attaining an adequate fit of the overwrapping film through such a 
thermal contraction treatment, there also exists the possibility of 
deformation of the printed display region occurring on the overwrapping 
film during, and as a result of, the thermal contraction treatment. 
Particularly, when a finished appearance is to be achieved by furnishing a 
metallic gloss to the printed display region, the harmful effects derived 
from such thermal contraction can be considerable. According to a solution 
taught by the prior art, hot stamping is executed for setting a metallic 
gloss to a cassette-tape overwrapping film. However, some problems 
inherent in this method include deviation of the stamping position due to 
a post-treatment, restriction on the stamping area, deterioration of the 
gloss resulting from finishing thermal contraction, difficulties in 
producing a continuous supply of products with satisfactory overwrapping, 
and an increase in the production cost. 
SUMMARY OF THE INVENTION 
In an attempt to eliminate the problems mentioned above, the present 
invention provides a new overwrapping film which is adapted to attain a 
tightly packed configuration by utilizing the thermal contraction property 
of a plastic base film. The overwrapping film according to the present 
invention comprises a plastic base film, an anchor coat layer formed by 
coating the the base film with a plastic material in a desired pattern, an 
ink layer of a desired pattern formed on the anchor coat layer, and an 
evaporated metal layer subsequently deposited on the ink layer in such a 
manner as to correspond in overall configuration to the anchor coat layer. 
On the plastic base film, then is formed a display pattern of the ink 
layer which is furnished with a metallic gloss by the evaporated metal 
layer. The plastic film base can be thermally contracted, and the 
evaporated metal layer sets the metallic gloss to the printed display 
pattern. 
OBJECTS OF THE INVENTION 
A primary object of the present invention is to provide an overwrapping 
film capable of achieving a tightly-packed configuration. 
Another object of the invention is to provide an overwrapping film having a 
printed display pattern with a metallic gloss. 
Still, another object of the present invention is to provide an 
overwrapping film where a printed display pattern thereof is rendered free 
from gloss deterioration or deformation despite a subsequent thermal 
contraction treatment. 
A further object of the present invention is to provide a method of 
producing an overwrapping film which has an improved display pattern which 
is rendered free from gloss deterioration despite a thermal contraction 
treatment.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In an overwrapping film 10 used for packing a tape cassette as illustrated 
in FIG. 1, a printed display region of a desired pattern as shown in an 
unfolded view of FIG. 2 is formed, by the process to be described below, 
on the film base 11 composed of a transparent plastic material such as 
polypropylene and having a specific, and known thermal coefficient of 
contraction. In FIG. 2, a transparent window 12 is formed for permitting 
visual recognition of an overwrapped object or a tape cassette, and 
characters representationally shown at 13 represent the name of a maker or 
other information and can be printed on the transparent window 12 with 
nontransparent black ink. A transparent heat seal portion 14 to be sealed 
by heat at the overwrapping time is formed along the peripheral edge of 
the overwrapping film 10 in a length corresponding to one tape cassette. 
Characters 15 can represent the type of the tape cassette to be 
overwrapped and can be displayed in silver which is the base color of an 
evaporated metal layer 25 deposited after the vacuum evaporation of 
aluminum. A data display region 16 can indicate necessary data and can be, 
for example, printed with black ink on a silver base. With the exception 
of the said transparent window 12, heat seal portion 14, characters 13, 
15, and data display region 16, the rest is a nontransparent portion 17 
which can, for example, be colored brown and can have a metallic gloss. 
One-dot chained lines 18A, 18B, 18C, 18D, 18E and 18F are shown in FIG. 2 
to merely denote folding lines for overwrapping and are not printed 
actually on the film 10. 
Subsequent to the printing performed by an apparatus 30 as schematically 
shown in FIG. 3, the overwrapping film 10 is treated by vacuum evaporation 
and is further rinsed with water so as to be cleansed. That is, in the 
arrangement of FIG. 3, of the base film 11, preferably made of a resin, 
particularly polyethylene, is forwarded from a first supply roller 31 and 
is coated with a plastic material 21 at a first printing block 32, except 
the areas of the base film 11 which corresponds to the transparent window 
12, and the heat seal portion 14 as illustrated in FIG. 4(A), so that an 
anchor coat layer 21 is formed thereon. Subsequently, after drying the 
anchor coat layer 21, the characters 13 and, for example, the data display 
region, are printed with ink in a second printing block 33, and further, 
the nontransparent part 17 is printed with ink which is preferably brown 
to form an ink layer 23 as illustrated in FIG. 4(B). In the next step 
subsequent to the drying of the ink layer 23, the transparent window 12 
and the heat seal portion 14 are coated with water-color ink in a third 
printing block 34 to form a water-color ink layer 24 as illustrated in 
FIG. 4(C). The film base 11 thus processed through the first, second and 
third printing blocks 32, 33 and 34 is wound on a second or take-up roller 
35 after drying the water-color ink. 
In addition to the above printing steps, vacuum evaporation of aluminum is 
executed on the entire side of the film base 11 to subsequently form an 
evaporated metal layer 25 as illustrated in FIG. 4(D). Consequently, a 
substrate composed of the base film, anchor layer, and ink layers is 
formed. Subsequently, the film base 11 is treated with shower rinsing so 
that, as illustrated in FIG. 4(E), the evaporated metal layer 25 is 
removed together with the water-color ink layer 24 formed on the 
transparent window 12 and the heat seal portion 14, thereby producing the 
overwrapping film 10 of FIG. 2. 
The overwrapping film 10 thus obtained has, on the film base 11, a 
multiplicity of continuous patterns each corresponding to one tape 
cassette as illustrated in FIG. 5. After the tape cassette is overwrapped 
with the film 10 folded along the one-dot chained lines 18A, 18B, 18C, 
18D, 18E and 18F, the overlapping heat seal portions 14 are thermally 
welded to each other by the application of heat at approximately 
200.degree. C. for a time of 0.5 seconds. Subsequently, the tape cassette 
packed with the overwrapping film 10 is heated for about 2 seconds in an 
atmosphere around 200.degree. C., so that the overwrapping film 10 is 
thermally contracted to render the overwrapping of the tape cassette 
adequately tight as illustrated in FIG. 1. 
In the overwrapping film 10 thus produced through the steps described 
hereinabove, the nontransparent part 17 is formed of the brown ink layer 
23 with a metallic gloss provided by the evaporated metal layer 25, and 
the characters 15 and the ground of the data display region 16 are shown 
in silver by the evaporated metal layer 25, hence presenting a remarkably 
appealing appearance. Moreover, the evaporated metal layer 25 can be 
removed with certainty from the transparent window 12 and the heat seal 
portion 14 in the rinsing step. Furthermore, in the thermal contraction 
step, which is executed primarily to attain a tightly-fit configuration, 
the ink layer 23 and the evaporated metal layer 25 formed on the anchor 
coat layer 21 are substantially free from exfoliation or deformation 
regardless of the thermal contraction of the film base 11, so that it 
becomes possible to achieve a satisfactory wrapped configuration of 
plastic film having a higher deformation yield rate and an overall lower 
cost of production when compared to the known hot stamping process. 
It is also to be noted that, by the provision of a connecting portion 25A 
to connect the repetitive pattern of the tape cassette as illustrated in 
FIG. 5, the evaporated metal layer 25 deposited on the reverse side of the 
film base 11 is utilizable as a grounding path for any static electricity 
generated during the wrapping of the tape cassette. 
From the foregoing, it is apparent that the objects of the present 
invention have been fully accomplished. As a result of the present 
invention, a novel process and apparatus for the overwrapping of objects, 
and particularly, cassettes, has been provided. Although a preferred 
embodiment of the principles of this invention has been described and 
illustrated in detail herein, it should be realized that the same are not 
limited to the particular configuration shown in the drawings, and that 
modifications thereof are contemplated and can be made without departing 
from the broad spirit and scope of this invention as defined in the 
appended claims.