EP1466831B1

EP1466831B1 - Sealed bag with unsealing tape

Info

Publication number: EP1466831B1
Application number: EP02786113A
Authority: EP
Inventors: Shuichi Goto; Yuichi Ohki
Original assignee: Idemitsu Unitech Co Ltd
Current assignee: Idemitsu Unitech Co Ltd
Priority date: 2001-12-18
Filing date: 2002-12-17
Publication date: 2008-01-23
Anticipated expiration: 2022-12-17
Also published as: DE60224845D1; DK1466831T3; CN1604867A; JPWO2003051729A1; WO2003051729A1; EP1466831A1; EP1466831A4; ATE384671T1; US20050063624A1; DE60224845T2; KR20040077856A

Abstract

A zipper 3 is stuck on the opening part 2 side of a packaging bag 1 and a heat-sealed part 12 is formed in the outer side from the zipper 3 to seal the packaging bag 1. A band-shaped unsealing tape 3 is stuck, in parallel to the opening part 2, on one inner surface of the packaging bag 1 in an area between the zipper 3 and the heat-sealed part 12. A cutout part 4 is formed on a surface opposite to the surface with the unsealing tape 3 stuck thereon at the end part of the unsealing tape 3. A pair of cut-in parts 5 are formed on the packaging bag 1 at the end part of the unsealing tape 3. <IMAGE>

Description

Technical Field

The present invention relates to a sealed bag with unsealing tape. More specifically this invention relates to a sealed bag with unsealing tape provided on the opening-part side of a packaging bag used for packaging foods, drugs or the like therein.

Background Art

Conventionally, bags (chuck bags) enable to be easily opened and closed by forming a zipper (an engaging device), which includes a male member and a female member, in an opening-part thereof have been used in many fields such as foods, drugs, daily commodities, and the like. Even with the bag with a zipper as described above, it is desirable that the bag is kept in the completely sealed state until the time point of sales, and generally an end part there of is completely sealed along the zipper part. In a case of a bag with a zipper which is completely sealed, generally a section between the zipper and a seal part in the opening-part side of the bag is cut in, and then the bag is opened and resealed at the zipper part.
For opening a sealed bag, a user generally cuts the bag with the conventional type of scissors or tears a part to be cut in with hands from an end part thereof. To facilitate the operation of tearing the part to be cut in with hands, sometimes a notch is formed at a side edge of the bag.
However, use of scissors is messy, and in addition, if scissors are not available, the bag can not be opened, which is disadvantageous. When a bag is torn from the notch, the bag can not be cut in along a straight line, which is also disadvantageous. To overcome the problems as described above, recently there has been proposed, for instance, the following means as a means for tearing a bag along a straight line manually and without using any tool such as scissors.
Means 1: Formation of a perforated line as a line for tearing on the opening-part side.
Means 2: Use of laminated film with the inner surface film relatively thick for forming a bag, and formation of a zipper on the inner surface film as well as a perforated line in a part outer from the zipper formed on the inner surface film and closer to an edge of the bag (Refer to Japanese Utility Model Publication No. S52-18254 ).
Means 3: Formation of a cutting-plane line having a specific form (Refer to Japanese Utility Model Publication No. S62-13838 )
However, each of the means described above has the problems as described below.
With the means 1, the sealing performance is rather low because of the use of a perforated line, and sometimes the bag employing the means I may be opened during transportation or in other similar situations.
With the means 2, an inner surface side film with a perforated line formed thereon itself can be tone along a straight line, but when the inner surface side film is thermally fused and stuck to the base film, the perforations are filled with materials from the base film due to the thermal effect, which disadvantageously makes it difficult to tear the bag.
With the means 3, the sealing performance is insufficient, and in addition the process for forming a specific cutting-plane line is disadvantageously complicated.
US-A-5116140 discloses a sealed bag with a tear string provided on a opening part side thereof, the sealed bag comprising a tear string stuck in parallel to said opening part on one inner surface of said packaging bag, wherein a cutout part is formed on a surface opposite to the surface with said tear string stuck thereon, on an end part side of said tear string of said packaging bag.
WO-A-80/02828 discloses a band-like tearing member.

Disclosure of the Invention

The present invention provides a sealed bag according to claim 1.
The present invention provides a sealed bag with unsealing tape which can provides the excellent sealing performance before its use and also which can easily be cut in and unsealed manually.
Adhesion of the unsealing tape is carried out by using an adhesive or thermally, for instance, by heat-sealing. The tape of the present invention is not limited to the one with the large width, but can be the one with the small width. Tape with the relatively smaller width is preferable because the tearing guide effect is higher. However, when the width is large, the higher tensile strength can be obtained even if the thickness is small. When the width is small, the high strength can be obtained by making the thickness larger.
With the present invention as described above, band-shaped unsealing tape is stuck on one inner surface of a packaging bag in parallel to the opening part thereof, and a perforated line or the like is not provided, and because of the configuration, there is not a space communicating to the outside, so that the excellent sealing performance before the packaging bag is opened is provided without fail.
Further, a cutout part is formed on a surface opposite to the surface with the unsealing tape stuck thereon at an end part of the unsealing tape of the packaging bag, therefore the cutout part is present on one surface of the packaging bag as well as on one surface of the unsealing tape, so that the end part of the unsealing tape is exposed in the cutout part and the cutout par can easily be raised.
In the sealed bag with unsealing tape according to the present invention, there is formed, on the packaging bag and/or on the unsealing tape, a pair of cut-in parts each cut in from an end part of the unsealing tape with the terminating edge present at a position inner from the end part of the unsealing tape.
With the present invention as described above, as a pair of cut-in parts are formed on the packaging bag and/or at end parts of the unsealing tape, a section between the cut-in parts functions like a tab, and the tab-formed section can be pinched as it is when unsealing the packaging bag, so that the operation for manually cut-in and unsealing the bag can easily be performed.
In the sealed bag with unsealing tape according to the present invention, the cut-in parts are preferably arranged diagonally against the unsealing tape with the base edges of the cut-in parts arranged outside the unsealing tape.
With the present invention as described above, as the cut-in part are inclined, even if a position at which the unsealing tape is stuck is slightly displaced from the regular position, cut-in parts can be formed correctly on one surface of the packaging bag as well as on the unsealing tape without fail. Especially, the pair of cut-in parts get closer in a direction toward the depth of the bag (in which cutting-in is performed), so that the cut-plane line can be guided to a specified position (such as a center line of the unsealing tape), and a desired and correct cut-plane line can be acquired without fail, even if the work for cutting in is performed manually.
In the sealed bag with unsealing tape according to the present invention, the unsealing tape is drawn uniaxially in the longitudinal direction.
Herein the term of "drawing" means physically drawing a polymeric material into the fiber-like or film-formed state. With this operation, the strength or elasticity modulus of the polymeric material can be improved, and when a crystalline polymer is drawn at a temperature higher than the glass transition temperature but lower than the melting point, molecules in the non-crystalline portion are drawn in the drawing direction with the crystallinity improved and the molecules are oriented in the drawing direction. As a result, the tensile strength and elasticity modulus become larger. Uniaxially drawing herein indicates drawing in one direction, and for instance, when a film is drawn uniaxially, the strength in the drawing direction becomes stronger than that in the vertical direction to provide an anisotropic material, and when the material is torn, the directivity for being torn in the drawing direction becomes higher.
Because of this feature, the draw ratio should be 5 times or more, and preferably in the range from 8 to 12 times. As the unsealing tape is uniaxially drawn in the longitudinal direction, the directivity in tearing becomes higher, and the bag can be unsealed linearly in the longitudinal direction of the unsealing tape.
In the sealed bag with unsealing tape according to the present invention, the unsealing tape is preferably made of polyolefin-based resin, and the polyolefin-based resin is preferably polyethylene-based resin or polypropylene-based resin.
As the polyolefin-based resin, there can be enlisted polyethylene, polypropylene, polybutene and the like.
As the polyethylene-based resin, there can be enlisted linear low density polyethylene (LLDPE), high density polyethylene (HDPE), low density polyethylene (LDPE) or the like.
As the polypropylene for producing polypropylene-based resin, there can be enlisted homopolypropylene, random polypropylene, block polypropylene and the like.
Because of the features described above, the unsealing tape is made of polyolefin-based resin, so that processing such as molding or drawing is performed easy because the polyolefin-based resin has the thermoplasticity,
Further, the polyethylene-based resin is excellent in the dampproof capability, waterproof capability, cold resistance, and chemical resistance, and is well adapted to use for packaging a product in the liquid state.
Further, the polypropylene-based resin has the small specific gravity, so that the resin can contribute to weight reduction of a packaging bag itself.
In the sealed bag according to the present invention, a zipper comprising a pair of male and female members is preferably stuck to both inner surfaces of the bag.
Because of the feature, a zipper comprising a pair of male and female members is stuck to both inner surfaces of the bag, and the zipper can repeatedly be opened or closed, so that the sealing performance of the bag can be maintained.

Brief Description of Drawings

Fig. 1 is a flat view showing a packaging bag according to one embodiment of the present invention;
Fig. 2 is an enlarged flat view showing a packaging bag according to the embodiment;
Fig. 3 is a cross-sectional view of the packaging bag taken along the line X-X in Fig. 2;
Fig. 4 is a view showing the procedure for opening the packaging bag according to the embodiment;
Fig. 5 is a view showing the procedure for producing the packaging bag according to the embodiment; and
Fig. 6 is a flat view showing a packaging bag according to another embodiment of the present invention.

Best mode for Carrying out the Invention

Embodiments of the present invention are described below with reference to the related drawings.
Fig. 1 shows a packaging bag 1 according to one embodiment of the present invention.
The packaging bag 1 comprises polyethylene sheets 10A (top side in the figure), 10B (rear side in the figure) sealed along the four edges thereof by means of heat sealing or the like. These sealed portions form a heat-sealed part 12. One edge of the rectangular packaging bag 1 functions as an opening part 2.
Unsealing tape 3 is wide tape made of polyolefin-based resin and is welded to the opening part 2 side on a surface of the polyethylene sheet 10B by heat sealing or the like, and is drawn uniaxially in the longitudinal direction.
A cutout part 4 is formed at an end part of the unsealing tape 3 of the packaging bag 1 on the opening part 2 side on a surface of the polyethylene sheet 10A and has a rectangular form.
A cut-in part 5 is formed at an end part of the unsealing tape 3 and is inclined from the polyethylene sheet 10B against an edge of the unsealing tape 3 so that the cut-in part 5 extends to inside of the unsealing tape 3. Further the cut-in part 5 is formed within a range of the cutout part 4. It is to be noted that the cutout part 4 and cut-in part 5 are provided both on heat-sealed parts 12 of two edges perpendicular to the opening section 2 in this embodiment.
A zipper 11 comprises a pair of a male member and a female member, which are stuck by heat sealing or the like under the unsealing tape 3 on the opening part 2 side to the polyethylene sheets 10A, 10B respectively. The zipper 11 is stuck to an inner surface of the packaging bag 1. The zipper 11 is made of polyethylene.
As shown in Fig. 2, the cutout part 4 is formed on the opening part 2 side and on a surface of the polyethylene sheet 10A and has a rectangular form, while the cut-in part 5 is positioned at an end part of the unsealing tape 3 in the outer side from the unsealing tape 3, and inclined from a cut-in part base end 5A positioned on the polyethylene sheet 10B, and extends to a cut-in part end part 5B positioned in the inner side from the unsealing tape 3.
The cut-in part end part 5B is formed in the inner side from the unsealing tape 3 as shown in Fig. 3 which is a cross-sectional view taken along the line X-X in Fig. 2.
As for the procedure for unsealing the packaging bag 1, as shown in Fig. 4, an end part of the unsealing tape 3 is pinched up, and then is pulled in the direction indicated by the arrow in the figure to tear the packaging bag 1. The section in which the polyethylene sheet 10B, unsealing tape 3, and polyethylene 10A are overlaid on each other is linearly torn from the cut-in part end part 5B in a direction parallel to the unsealing tape 3.
As for the procedure for manufacturing the packaging bag 1, as shown in Fig. 5, at first, the unsealing tape 3 is held between the polyethylene sheets 10A, 10B. The cutout part 4 is formed at a position corresponding to the unsealing tape 3 on the polyethylene sheet 10A. The polyethylene sheets 10A, 10B, and the unsealing tape 3 are heated, melted and stuck to each other by a heat seal bar 20, and a heat-sealed part 12 is formed at a position corresponding to the cutout part 4.
Then two sets of cut-in parts 5 widening toward the end and each extending over an edge of the unsealing tape 3 are formed within the cutout parts 4. In this step, the two sets of cut-in parts 5 widening toward the end are opposite to each other.
The section in which the polyethylene sheet 10B, unsealing tape 3, and polyethylene sheet 10A are overlaid on each other is cut in with a cut-in part bar 30 between the two sets of cut-in parts 5.
With the steps described above, the polyethylene sheets 10B with the two sets of cutout parts 4 and cut-in parts 5 formed thereon, unsealing tape 3, and polyethylene sheets 10A are laminated to form a laminated body, and heat-sealed parts are formed along two edges each perpendicular to the heat-sealed part 12 shown in the figure, thus a packaging bag being formed.
With the embodiment as described above, the advantages as described below are provided.

(1) The cut-in parts 5 inclining against edges of the unsealing tape 3 and extending to inside of the unsealing tape 3 are formed at an end part of the unsealing tape 3, and the cut-in parts 5 can be pinched as they are as a finger grip, so that the operation of manually unsealing the bag can easily be performed.
Further, as the cut-in parts 5 are inclined, therefore even if the unsealing tape 3 is stuck at a position slightly displaced from the regular position, the cut-in parts 5 can be formed without fail on a surface of the polyethylene sheet 10B of the packaging bag 1 as well as on the unsealing tape 3.
In addition, the packaging bag 1 comprises the band-shaped unsealing tape 3 which is stuck on one inner surface of the packaging bag 1 in parallel to the opening part 2, and a perforated line or the like is not required to be formed thereon, so that a space communicating to the outside is not generated, which ensures the sealing performance before the packaging bag 1 is unsealed.
(2) The cutout part 4 is formed on an inner surface opposite to that on which the unsealing tape 3 is stuck at an end part of the unsealing tape 3 of the packaging bag 1, and therefore the cutout part 4 is present only on the unsealing tape 3 and on the polyethylene sheet 10A of the packaging bag 1, so that the cutout part 4 is thin and the cut-in part 5 can easily be raised.
(3) The unsealing tape 3 is uniaxially drawn in the longitudinal direction, and the directivity in tearing becomes higher, so that the packaging bag 1 can linearly be unsealed in the longitudinal direction of the unsealing tape 3.

The cut-in part 5 inclines from the cut-in part base end 5A positioned in the outer side from the unsealing tape 3 and extends to the cut-in end parts 5B positioned in the inner side from the unsealing tape 3. In an alternative embodiment, not covered by the appended claims the cut-in part 5 may have the cut-in part base end 5A positioned in the inner side from the unsealing tape 3.
In this case, the cut-in part 5 may not incline, and the pair of cut-in parts may be, for instance, parallel to each other as shown in Fig. 6.
Although the cutout parts 4 and cut-in parts 5 are formed at both end parts of the unsealing tape 3 respectively in the embodiment described above, the configuration is allowable in which the cutout part and the cut-in part are formed only at one end part (namely, only in the right or left side of the bag shown in Fig. 2 and Fig. 6).
The unsealing tape 3 is not limited to that having a relatively large width as described in the embodiment above, and also the unsealing tape having a small width may be used so long as the tensile strength providing the tearing guide effect can be obtained.
Further, the zipper 11 is stuck to the opening part 2 side in the embodiment described above, but may not be provided. In this case, the packaging bag is adapted to be used as a disposable bag.
The unsealing tape 3 is made of polyethylene in the embodiment described above, but the material is not limited to polyethylene, and the unsealing tape 3 may be made of polypropylene.
In addition, structures, forms and the like for carrying out the present invention may be different from those described above within the range in which the object of the present invention can be achieved.

Industrial Availability

The present invention can be applied to packaging bags for packing foods, drugs, and the like therein, especially as a sealed bag with unsealing tape, an opening part side of which can easily be unsealed.

Claims

A sealed bag (1) comprising two opposed sheets (10A, 10B) each having an inner and an outer surface,
said sealed bag comprising an unsealing tape (3) being stuck in parallel to an opening part (2) on an inner surface of one of said sheets (10B), wherein a cutout part (4) is formed in the other sheet (10A) opposite to an end part of said unsealing tape (3), characterized in that the unsealing tape (3) is band-shaped; in that said unsealing tape (3) is uniaxially drawn in the longitudinal direction; and in that a pair of cut-in parts (5) are formed on the one of said sheets (10B) and/or said unsealing tape and extend from an edge of said unsealing tape (3) with cut-in end parts (5B) positioned inwards of the edge of the cut-in Parts (5).
The sealed bag with unsealing tape according to claim 1, wherein
said cut-in parts (5) are inclined against said unsealing tape (3), and a base end of each cut-in part is present outside said unsealing tape.
The sealed bag with unsealing tape according to claim 1 or claim 2, wherein
said unsealing tape (3) is made of polyolefin-based resin.
The sealed bag with unsealing tape according to claim 3, wherein
said polyolefin-based resin is polyethylene-based resin.
The sealed bag with unsealing tape according to claim 3, wherein
said polyolefin-based resin is polypropylene-based resin.
The sealed bag with unsealing tape according to any of claims 1 to 5, wherein
a zipper (11) comprising a pair of a male member and a female member is stuck to both inner surfaces of the bag respectively.