US20050262809A1

US20050262809A1 - Method for producing package

Info

Publication number: US20050262809A1
Application number: US11/138,501
Authority: US
Inventors: Futoshi Tada; Katsuhiko Kumakura; Tozo Umeda; Kinji Uemura
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2004-05-27
Filing date: 2005-05-27
Publication date: 2005-12-01
Also published as: HK1082943A1; CN100396577C; JP2005335770A; CN1680173A

Abstract

The present invention provides a package realizing a simpler structure, simpler production process, lower product cost, lower production cost, higher strength and excellent appearance. The package is produced by successively forming, on a first surface of a light permeable base, a first printing layer, an anti-offset layer and a second printing layer in a single printing step to give a backing sheet, and allowing the backing sheet to hold an article at the side of a second surface of the base.

Description

FIELD OF THE INVENTION

The present invention relates to a package accommodating an article such as a battery and a method for producing the same.

BACKGROUND OF THE INVENTION

Product packages accommodating articles such as batteries, daily necessities including facial cleansing items, and processed foods have been widely used. From the viewpoint of effective display at stores/shops and low cost, blister packs are widely used for the containers of product packages. The product packages employing blister packs are composed of a blister pack, a laminate layer and a backing sheet (paper, for example) laminated in this order.
More specifically, printing is given on both surfaces of the backing sheet. The blister pack and the laminate layer are bonded by heat sealing. The laminate layer and the backing sheet are adhered by an adhesive. This yields a complicated laminate structure composed of the blister pack, the laminate layer, the adhesive layer, the printing layer, the backing sheet and the printing layer.
Moreover, the existence of the adhesive layer is problematic because it makes the structure complicated and increases the cost. Particularly because two different adhesion methods are used, the production process is complicated.
Further, in these days, considering the consequences to the natural environment, biodegradable resins capable of being decomposed and disappearing in the natural environment with the passage of time are being used as the material for product packages in place of conventional thermoplastic resins such as polyethylene and polyethylene terephthalate (see Japanese Laid-Open Patent Publications Nos. Hei 10-100353 and 2001-130183, for example). The use of such biodegradable resins is accompanied by the problems that they are difficult to control because the temperature range in which they are heat sealed is limited; and that the use thereof can cause variations in adhesion strength and quality.
Further, adhesives have poorer adhesion strength than heat sealing. The fact is that adhesives suitable for biodegradable resins have not been found yet.
For product packages, further improvement is currently desired to achieve a simpler structure, simpler production process, lower product cost, lower production cost, higher package strength and better appearance. In other words, improvement of product packages having the laminate structure described above is required.
In view of the above, an object of the present invention is to overcome the above problems and to provide a package that can realize a simpler structure, simpler production process, lower product cost, lower production cost, excellent strength and excellent appearance.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a method for producing a package comprising the steps of: (1) successively forming, onto a first surface of a light permeable base, a first printing layer, an anti-offset layer and a second printing layer by a single printing step to give a backing sheet; and (2) allowing the backing sheet to hold an article at the side of a second surface of the base.
In the step (2), it is effective that a container accommodating the article be integrated with the second surface to allow the backing sheet to hold the article. It is further effective that the container is bonded to the second surface by heat sealing.
According to the present invention, a single production step can form, on a first surface of a light-permeable and transparent base, both a printing layer that can be observed from the first surface and a printing layer that can be observed from a second surface, which is opposite to the first surface, whereby a package having a simple structure without a laminate layer and an adhesive layer can be produced. Thus, reduction of product cost and production cost can be achieved.
While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a diagram for explaining a conventional printing method.
FIG. 2 is a diagram for explaining the disadvantages of a conventional printing method.
FIG. 3 is a diagram for explaining a printing method according to the present invention.
FIG. 4 is an exploded perspective view schematically illustrating an embodiment of a package according to the present invention.
FIG. 5 is a vertical cross sectional view of a package shown in FIG. 4 after assembled.
FIG. 6 is an exploded perspective view schematically illustrating another embodiment of a package according to the present invention.
FIG. 7 is a diagram showing test specimens for evaluating peeling strength.
FIG. 8 is a diagram showing how to evaluate abrasion resistance.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for producing a package comprising the steps of: (1) successively forming, onto a first surface of a light permeable base, a first printing layer, an anti-offset layer and a second printing layer by a single printing step to give a backing sheet; and (2) allowing the backing sheet to hold an article at the side of a second surface of the base.
Hereinafter, a case in which the printing layers are laminated by a conventional printing method will be described briefly.
FIG. 1 is a diagram for explaining a conventional printing method.
As shown in FIG. 1, in a step (a), an original material having a length of 1000 m serving as a base 1 is fed from a roll unit 2 to a roller 3, which is then sent along the roller 3 and printed with a first color ink, a second color ink, a third color ink and a fourth color ink by a printing roller 4, a printing roller 5, a printing roller 6 and a printing roller 7, respectively. Thereby, a first printing layer is formed. Reference numerals 4 a, 5 a, 6 a and 7 a denote UV lamps for curing UV inks. On one surface of the base fed along the roller 3 is formed the first printing layer by the first printing using, for example, four different color inks. The base is again rolled up by a roll unit 8.
In a subsequent step (b), the base is again fed from the roll unit 8, and then an anti-offset layer is formed on the upper surface of the first printing layer by flexographic printing (by means of a printing roller 9 and a UV lamp 9) with the use of a white ink, which is then rolled up by a roll unit 10.
Finally, in a step (c), the base is again fed from the roll unit 10, and then a second printing layer with, for example, four different color inks is printed on the upper surface of the anti-offset layer.
Similar to the above, the base is fed along a roller 11 and printed with a first color ink, a second color ink, a third color ink and a fourth color ink by a printing roller 14, a printing roller 15, a printing roller 16 and a printing roller 17, respectively, to form a second printing layer. Reference numerals 14 a, 15 a, 16 a and 17 a denote UV lamps for curing UV inks.
When trying to produce a package according to the present invention by such conventional printing method, because the printing steps are not continuously performed and the base has to be rolled up in each printing step, the following problems occur.
As an example, the following case is assumed. In the case of printing a plurality of first printing layers 20, each with a length of 120 mm, a spacing of 5 mm (i.e. a pitch of 125 mm) and an arbitrary width, on the surface of a longitudinal base 1 as shown in FIG. 2 a, because, in the first printing in which the long base is fed and rolled up and the base contacts with the rollers in the printing device, the base contracts and expands, causing variations in length ranging from 998 m (with a pitch of 124.75 mm) to 1002 m (with a pitch of 125.25 mm).
If the base contracts to have a length of 998 m, the pitch of the first printing layer will be 124.75 mm. There will be no problem in the step (b), because the step (b) forms a white printing layer as an anti-offset layer. In the step (c) where the second printing layer is formed by the second printing, however, first-produced first printing layer 20 a and second printing layer 21 a will be misaligned with each other with a difference of 0.25 mm. In the 100th one, the difference between a first printing layer 20 b and a second printing layer 21 b will be 25 mm. In the 1000th one, the difference between a first printing layer 20 c and a second printing layer 21 c will be 250 mm. In the last 8000th one, the difference between a first printing layer 20 d and a second printing layer 21 d will be 2 m (as shown in FIG. 2 b).
In short, the production of a package according to the present invention using a conventional printing method is accompanied by the problem that the printing misalignment occurs and the yield cannot be improved.
In view of the above, in the present invention, a device shown in FIG. 3 is used. In a step (1), a first printing, a flexographic printing and a second printing are continuously performed to successively form, on a first surface of a longitudinal, light permeable (transparent) base 30, for example, a first printing layer with four different color inks, an anti-offset layer with a white ink and a second printing layer with three different color inks. Thereby, a backing sheet is produced. Subsequently, a step (2) allows the backing sheet to hold an article at the side of the second surface of the base.
According to this, the number of the rolling-up steps of the base is reduced, and the base does not slide in the printing device. Accordingly, the contraction and expansion can be minimized, and the yield can be improved.
More specifically, as shown in FIG. 3, a longitudinal base 30 is fed along a roller 33. Then, a first color ink, a second color ink, a third color ink and a fourth color ink are printed by a printing roller 34, a printing roller 35, a printing roller 36 and a printing roller 37, respectively, to form a first printing layer with four different color inks. Behind each printing roller is placed a UV lamp 34 a, 35 a, 36 a or 37 a for curing a UV ink.
The base 30 is then sent to a flexographic printing roller 40 where an anti-offset layer having a white ink is formed using a UV lamp 40 a. The base 30 is then sent along a roller 41, and a first color ink, a second color ink and a third color ink are printed by printing rollers 44, 45 and 46, respectively, to form a second printing layer with three different color inks. Behind each printing roller is placed a UV lamp 44 a, 45 a or 46 a for curing a UV ink. Finally, the base 30 is rolled up by a roll unit 48.
The first printing layer and the second printing layer are preferably formed by relief printing or gravure printing. From the viewpoint of achieving extremely fine printing, relief printing is more preferred. The anti-offset layer is preferably formed by flexographic printing or screen printing. From the viewpoint of speed and mass productivity, flexographic printing is more preferred.
Hereinafter, a description will be given of a package according to the present invention referring to the accompanying drawings.
FIG. 4 is an exploded perspective view schematically illustrating an embodiment of a package according to the present invention. As shown in FIG. 4, a package 101 according to the present invention includes a backing sheet 102, a battery group 104 as an article, and a container 103 for allowing the backing sheet to hold the battery group 104.
FIG. 5 is a vertical cross sectional view of the package shown in FIG. 4 after assembled. As shown in FIG. 5, the package 101 of the present invention has a light permeable base 102 a, and a backing sheet 102 including a first printing layer 102 b, an anti-offset layer 102 c and a second printing layer 102 d which are laminated in this order on a first surface of the base 102 a. The package 101 further includes a container 103 as a holding means for allowing the backing sheet 102 to hold the battery group 104 at a second surface of the base 102 a.
In a conventional package, printing is given on the front surface and the back surface of a base whereas in a package according to the present invention, printing is given only on one surface to form both a second printing layer 102 d to be observed from the back surface of the base and a first printing layer 102 b to be observed from the front surface of the base.
In other words, in a package according to the present invention, printings such as designs and instructions to be observed from the directions indicated by the arrows X and Y in FIG. 5 are given on the first surface of the base 102 a. This structure can omit a laminate layer and an adhesive layer provided between the container 103 and the base 102 a in a conventional package.
In order to prevent the first printing layer 102 b to be observed through from the direction of the arrow Y, or conversely, to prevent the second printing layer 102 d to be observed through from the direction of the arrow X (in other words, in order to prevent offseting), an anti-offset layer 102 c is provided between the first printing layer 102 b and the second printing layer 102 d. The anti-offset layer 102 c should have a shielding effect enough to, for example, read a barcode contained in the first printing layer 102 d from the direction of the arrow Y.
The first printing layer 102 b and the second printing layer 102 d are formed using, for example, an ordinary ink such as ultraviolet curing (UV) ink. The first printing layer 102 b and the second printing layer 102 d have a thickness of about 4.0 to 6.0.
The anti-offset layer 102 c may be formed with the same ink as the first printing layer 102 b and the second printing layer 102 d. The thickness and the composition thereof can be adjusted as long as the above shielding effect can be exhibited. For example, the anti-offset layer 102 c preferably has a thickness of 10.0 to 15.0 μm, and is preferably formed with a light impermeable white ink.
The first printing layer 102 b and the second printing layer 102 d are preferably formed by relief printing or gravure printing. As for the anti-offset layer 102 c, it is preferably formed by flexographic printing because it should have a certain thickness to exhibit the shielding effect.
And, by bonding the container 103 and the base 102 a of the backing sheet 102 by means of heat sealing to form a whole, the backing sheet 102 is allowed to hold the battery group 104 at the side of the second surface of the base 102 a. The backing sheet 102 may have a hanging aperture 105 so that the package 101 can be hanged on a sale shelf for display.
The above-described backing sheet 102 in the present invention can be applied to other packages. FIG. 6 is an exploded perspective view schematically illustrating another embodiment of a package according to the present invention. The package 111 shown in FIG. 6 includes a backing sheet 112 and a transparent container 113. The container 113 contains a battery group 114 therein.
In this embodiment also, the same backing sheet as the backing sheet 102 of FIGS. 4 and 5 can be used as the backing sheet 112. Accordingly, a laminate layer and an adhesive layer are not formed on the surface of the backing sheet 112 to be in contact with the container 113, and folds 113 a, 113 b and 113 c may be formed at the side opposite to the container 113.
More specifically, the periphery of the container 113 is folded by 180 degrees on the backing sheet 112 side to form the folds. In the direction of the alternate long and short dash lines (the arrow Z), the backing sheet 112 is slid into the folds 113 a and 113 c from the edges thereof. When the backing sheet 112 reaches the fold 113 b, the backing sheet 112 and the container 113 are integrated.
Since the backing sheet 112 is merely inserted in the folds 113 a, 113 b and 113 c of the container 113, the backing sheet 112 is preferably fixed with the folds 113 a, 113 b and 113 c. Any means may be used to the fixing without particular limitation. Examples thereof include heat sealing, an adhesive and a stapler. Particularly, heat sealing is preferred.
Similar to the case of FIGS. 4 and 5, the backing sheet 112 may have a hanging aperture 115 so that the package 111 can be hanged on a sale shelf for display.
In the packages shown in FIGS. 4 to 6, the base for constituting the backing sheet 102, 112 is transparent. It is further preferred that the containers 103 and 113 be transparent so that the design printed on the outer jacket of the batteries in the battery groups 104 and 114 can be observed by a user or a customer.
The backing sheet in the present invention is applicable not only to the packages using blister packs shown in FIGS. 4 to 6, but also to those using so-called skin packs and shrink packs.
It is preferred that either of the base and the container in the package according to the present invention be made of a biodegradable resin.
Examples of the biodegradable resin that can be used in the present invention include aliphatic polyester, modified polyvinyl alcohol (PVA), cellulose ester compounds and modified starch. Among them, the aliphatic polyester is environmentally preferred because alcohol and carboxylic acid generated therefrom during decomposition are extremely less toxic.
Examples of the aliphatic polyester include polymers produced by microorganism-mediated processes such as a hydroxybutyric acid-valeric acid polymer, synthetic polymers such as polycaprolactone and an aliphatic dicarboxylic acid-aliphatic diol condensate and semisynthetic polymers such as polylactic polymers.
From the viewpoint of excellent transparency, stiffness, heat resistance and workability, the polylactic polymers are preferably used. The polylactic polymer may be a homopolymer of L-lactic acid and/or D-lactic acid. Alternatively, it may be a copolymer or a mixture (or a polymer alloy) with other hydroxycarboxylic acids as long as its biodegradability is not impaired.
Examples of the other hydroxycarboxylic acids include glycolic acid, 3-hydroxybutylic acid, 4-hydroxybutylic acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid and 6-hydroxycaproic acid.
The polylactic polymer, a preferred biodegradable resin, preferably has, but not limited to, a weight-average molecular weight in the range of 50,000 to 300,000. When the weight-average molecular weight is less than 50,000, practical physical properties may hardly be exhibited. Conversely, when the weight-average molecular weight exceeds 300,000, melt viscosity may be too high, resulting in poor moldability.
The polylactic polymer has a high glass transition point and high crystallinity, and it has characteristics similar to those of polyethylene terephthalate (PET). Further, a film made of the polylactic acid can be uniaxially or biaxially drawn (stretched). The resulting drawn sheet, in which molecules are oriented, is low in brittleness, hard to crack and extremely favorable in strength. Moreover, the polylactic polymer film can be formed by extrusion casting, which ensures transparency of the film. In the present invention, a drawn sheet is preferably used as a material to produce a container particularly by vacuum/pressure forming.
A raw material for the polylactic polymer may be corn. Starch is separated from corn and then converted into sugar. Lactic acid is then obtained by lactic acid fermentation, which is converted into lactide, and then polymerized into polylactic acid. As just described, the polylactic polymer can be made without using petroleum materials. Therefore, according to the present invention, the final resulting battery package as well as the preparation process of the raw material are environmentally friendly.
The biodegradable resin may be a resin composition. In this case, the biodegradable resin may be mixed with other polymeric materials as long as the effect of the present invention is not impaired. Alternatively, in order to control the physical properties and workability, the biodegradable resin may be mixed with a plasticizer, a lubricant, an inorganic filler, an ultraviolet absorber, a heat stabilizer, a light stabilizer, a light absorber, a coloring agent, a pigment and a modifier.
In particular, it is necessary to mold the container of the battery package to have a holder portion, which is relatively precisely designed to fit the battery shape. In other words, the container requires not only the transparency but also moldability. However, since the biodegradable resin has brittleness, it may be cracked under the conventional molding conditions.
To solve the problem, in the present invention, it is preferred to form the container using a drawn sheet of biodegradable resin. Due to the drawing, the resulting sheet has improved brittleness and improved strength. Thereby, a container highly resistant to cracking can be produced. A biaxially drawn sheet is more preferred than a uniaxially drawn sheet because a biaxially drawn sheet has high strength. This drawn sheet is formed into a container by a conventional method.
The drawn sheet preferably has a tensile strength (breaking strength) of 40 to 90 MPa. When the tensile strength is less than 40 MPa, sufficient strength to carry the battery cannot be obtained. Conversely, when the tensile strength is greater than 90 MPa, the sheet strength will be too high, decreasing moldability and transparency of the sheet. Particularly preferred is 60 to 80 MPa. The tensile strength in the present invention is measured according to JIS K 7127 in which a Type 2 test specimen is used and measurement is made at a test rate of 200 mm/min.
Further, the drawn sheet preferably has a tensile elasticity of 1 to 7 GPa. When the drawn sheet has a tensile elasticity of less than 1 GPa, the sheet will be too stiff, decreasing moldability of the sheet. When the drawn sheet has a tensile elasticity exceeding 7 GPa, the sheet will be too soft, which may cause difficulty in carrying the battery. Particularly preferred is 2 to 6 GPa. The tensile elasticity can be measured according to JIS K 7127.
As an index of the sheet transparency, the drawn sheet preferably has a haze of less than 15%. When the haze is not less than 15%, the sheet will have decreased transparency, losing the inherent function of the package. Particularly preferred is 2 to 12%. The haze is measured according to JIS K 7105.
The container can contain a battery group including a plurality of batteries wrapped in a shrink pack as an article. This shrink pack is also preferably made of a biodegradable aliphatic polyester. The biodegradable aliphatic polyester is preferably a polylactic polymer. The shrink pack is preferably formed of a drawn sheet of the biodegradable aliphatic polyester.
The base of the package according to the present invention preferably has a thickness of 50 to 200 μm. When the base has a thickness of less than 50 μm, the resulting sheet will be too thin, which may cause difficulty in carrying the article. When the base has a thickness exceeding 200 μm, thermal conductivity will be decreased, causing variations in adhesion strength when the base and the container are heat-sealed, resulting in a final package of lower quality. Besides, it is difficult to control heat during the heat sealing process.
The present invention will be described below in further detail by way of examples, but it is to be understood that the present invention is not limited thereto.

EXAMPLE 1

In this example, a package according to the present invention having the structure shown in FIGS. 4 and 5 was produced using a printing device having the structure shown in FIG. 3.
As the light permeable base 102 a, a 150 μm thick translucent drawn sheet made of polylactic acid (PLA) was prepared. The base had a tensile strength (breaking strength) of 110 MPa both in length and width directions, and a tensile elasticity of 3.8 GPa in length direction and 4.3 GPa in width direction. The heat shrinkage of the base was measured according to JIS Z 1712 in which a test specimen was heated at 120° C. for 5 minutes. As a result, the base had a heat shrinkage of 2.7% in length direction and 0.3% in width direction.
On one surface of the base 102 a were successively formed a 5 μm thick first printing layer 102 b made of UV ink by relief printing, a 12 μm thick anti-offset layer 102 c made of UV ink by flexographic printing, and a 5 μm thick second printing layer 102 d by relief printing in a single rotary printing step. Thus, a backing sheet 102 was obtained.
Subsequently, a 250 μm thick transparent drawn sheet made of PLA was prepared. The drawn sheet had a tensile strength (breaking strength) of 66 MPa in length direction and 65 MPa in width direction, a tensile elasticity of 3.2 GPa in length direction and 3.1 GPa in width direction, and a haze of 10%. The heat shrinkage of the drawn sheet was measured according to JIS Z 1712 in which a test specimen was heated at 120° C. for 5 minutes. As a result, the drawn sheet had a heat shrinkage of 3.7% in length direction and 1.7% in width direction. This drawn sheet was molded into a container 103 having the shape shown in FIGS. 4 and 5.
Finally, a battery group 104 (shrink-packed) including four cylindrical AA batteries was prepared. The battery group 104 was housed in the holder portion of the container 103. The brim of the container 103 and the base 102 a of the backing sheet 102 were bonded by heat sealing at a heating temperature of 100° C. Thus, a package “A” according to the present invention was produced.

EXAMPLE 2

A package “B” according to the present invention was produced in the same manner as in EXAMPLE 1 except that the base 102 a and the container 103 were made using a drawn sheet of polyethylene terephthalate (PET) having a tensile strength (breaking strength) of 68 MPa both in length and width directions, a tensile elasticity of 2.1 GPa in length direction and 2.2 GPa in width direction, and a haze of less than 1%, instead of using a drawn sheet of PLA.

COMPARATIVE EXAMPLE 1

A package “C” for comparison was produced in the same manner as in EXAMPLE 1 except for the following points. A first printing layer was formed on the second surface of the base 102 a by relief printing. A 50 μm thick transparent drawn sheet made of PLA serving as a laminate layer was bonded on the first printing layer using a polyamide adhesive. Further, a second printing layer was formed on the first surface of the base 102 a by relief printing. Finally, the laminate layer and the container were bonded by heat sealing.

COMPARATIVE EXAMPLE 2

A package “D” for comparison was produced in the same manner as in EXAMPLE 1 except that the anti-offset layer by flexographic printing was not formed.
[Evaluation]
(1) Peeling Strength
Peeling strength was measured as follows. A test specimen 121 obtained by cutting the backing sheet of each package into a strip with a width of 10 mm and a test specimen 122 obtained by cutting the drawn sheet constituting the container of each package into a strip with a width of 10 mm were bonded with a 6 mm long overlap 123 by heat sealing as shown in FIG. 7. FIG. 7 is a diagram showing test specimens for evaluating peeling strength.
Then, a so-called T type peeling test was performed using a digital force gauge available from IMADA Co., Ltd. Specifically, the ends of the test specimens were pulled in opposite directions as shown in FIG. 7 at a rate of 200 mm/min, during which strength necessary for the peeling was measured. The results are shown in Table 1. A larger value is preferred because the larger the value, the higher the peeling strength.
(2) Abrasion Resistance
The abrasion resistance of the back surface of the backing sheet 102 (the first surface side of the base 102 a), that is, the surface to which the container 103 was not bonded, was evaluated. As shown in FIG. 8, a corrugated cardboard 125, from which boxes used for packing and transporting the battery packages would be made, was adhered to a 0.9 kg weight 124 to give a slider 126. FIG. 8 is a diagram showing how to evaluate abrasion resistance.
The backing sheet 102 of each package was fixed. The slider 126 was then moved back and forth 500 times on the backing sheet 102, after which assessment was made. A rating of good was given when letters of the second printing layer was clearly seen. A rating of fair was given when they were a little difficult to be seen. A rating of bad was given when they were unreadable. The results are shown in Table 1.
(3) Degree of offset

Each of the packages “A” to “D” was visually checked from both the front surface side and the back surface side to see whether the first printing layer and the second printing layer were unintentionally transferred, i.e. whether an offset was seen. A rating of good was given when an offset was seen. A rating of fair was given when a slight offset was seen. A rating of bad was given when the degree of offset was high. The results are shown in Table 1.

TABLE 1


		Abrasion
	Peeling	resistance
Components of backing sheet	strength	0.9 Kg	Offset

Ex. 1	Second printing layer/	15.3 N	good	good
	Anti-offset layer/
	First printing layer/Base (PLA)
Ex. 2	Second printing layer/	13.5 N	good	good
	Anti-offset layer/
	First printing layer/Base (PET)
Comp.	Second printing layer/	10.1 N	good	good
Ex. 1	Base (PLA)/First printing layer/
	Laminate layer
Comp.	Second printing layer/	15.3 N	good	fair
Ex. 2	First printing layer/Base (PLA)

Table 1 shows the components of backing sheet, the peeling strength, the abrasion resistance and the degree of offset for the packages “A” to “D”. It is clear, from Table 1, that the packages “A” and “B” of EXAMPLEs 1 and 2 of the present invention were excellent on all items.
The above-described package according to the present invention having excellent strength and excellent abrasion resistance can be produced by a simpler method than a conventional method. Further, the package according to the present invention is effectively used as a package capable of containing any article including batteries and of being hanged at stores and shops. Particularly, because a biodegradable resin is used as the material, the package according to the present invention is preferably used as an environmentally friendly package.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains, after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.

Claims

1. A method for producing a package comprising the steps of:

(1) successively forming, onto a first surface of a light permeable base, a first printing layer, an anti-offset layer and a second printing layer by a single printing step to give a backing sheet; and

(2) allowing said backing sheet to hold an article at the side of a second surface of said base.

2. The method for producing a package in accordance with claim 1, wherein, in said step (2), a container accommodating said article is integrated with said second surface to allow said backing sheet to hold said article.

3. The method for producing a package in accordance with claim 2, wherein said container is bonded to said second surface by heat sealing.