DE69837082T2 - Easy-to-open arrangement on a gas-tight, shrunken bag - Google Patents

Abstract

The invention relates to a pouch or bag (1) of a heat shrinkable gas-barrier, thermoplastic film for packaging one or a plurality of items, said pouch or bag comprising a closed bottom (2), two closed side edges (3) and (4) and an open mouth (5) for the introduction of the items to be packaged, said pouch or bag being characterized in that it comprises a seal (6) along a line, in-between the bottom (2) and the mouth (5), connecting the two side edges (3) and (4), said seal (6) defining with the closed bottom (2) and part of the side edges (3') and (4') a closed, airtight area (7) and in that it further comprises another seal (8) extending from the closed bottom (2) toward the closed, airtight area (7) and a precut (9) made in the area delimited by the bottom (2) and the seal (8). The invention is particularly useful for vacuum packaging of food, wherein the product is introduced into the pouch or bag previously described, that is then vacuumised, the mouth (5) is sealed and the package is submitted to heat treatment. <IMAGE>

Description

The The invention relates to a bag or bag made of a heat-shrinkable, thermoplastic gas barrier film for packaging one or more several items and a method of packaging an article in this bag or this bag.

specially The invention relates to an easy-open bag or a light to be opened Bag for Vacuum shrink packaging, which is characterized in that he / she has two edges which are easy to grip, which makes opening easier.

One packaging methods, which are common today, are vacuum shrink packaging, at the desired one Article with a heat-shrinkable, wrapped in thermoplastic film, which is in the form of a bag, a film folded in two layers or the like is present, and the pack evacuated, heat-sealed and is cut along the edge areas. The resulting package is heat shrunk, around for to provide a tight look. The heat shrink packaging wins increasing popularity because they add to the aesthetic appeal the packaged article contributes and thereby increasing their commercial value and easy packaging of articles, even if they have complex shapes.

on the other hand have with heat shrinkable Foil wrapped Packaging has the disadvantage that wraps so close to the underlying surfaces adhere and are under such tension that they are difficult to tear, if the packaging has to be torn open.

Various Methods have hitherto been proposed to overcome this problem and the opening of packaging made from heat-shrunk foils. These methods include: i) Formation of a perforation line in a certain position on a heat-shrinkable Foil, so that the package can be opened by tearing along this line; ii) production of a U-shaped Holes at a specific location on the slide and attaching a Paper seal over the hole to form a seal label, which as an aid in opening the Packing is used; and iii) additional Attaching a so-called "opening band".

Indeed These conventional methods have their own limitations. The first approach grows during heat treatment the heat-shrinkable Foil the size of the perforations, and Impurities can potentially through the holes get into the pack, reducing the commercial value of the contents is reduced. In some cases can the perforations during tearing the handling. The second approach is needed a special device for the production of the U-shaped hole and also increases the Use of paper seals the manufacturing cost. These two procedures are not suitable for Vacuum packages. The third approach has the inherent disadvantage of being cumbersome too be.

One further for heat-shrunk Bags available easy to open System is disclosed in EP-A1-745 539, where a heat-shrinkable film wrap for a Food product a peripheral zone, by a seal between opposite Film layers is separated from the rest, and has a cut, which extends in the zone from one edge inwards, with it during heat shrinkage a tongue is formed to facilitate opening. The foil is wrapped around the product, peripherally heat sealed and then heat shrunk. The zone is preferably separate from and adjacent to the pack lock heat seal and may be peripheral or over theirs whole area heat sealed be. The foil may contain a pouch for packaging the product Be vacuum or allow packaging under a modified atmosphere.

This System has the disadvantage that after shrinking the outstanding Tongue is not visible and difficult to grip, resulting in an unpleasant Appearance and sometimes even accidental breakage of the packaging leads. There is therefore a need for a safe, easy-to-open System with a better appearance of the packaging.

NL-A-6 900 418 discloses a bag with the in the preamble of claim 1 contained features.

The Inventors have found that when in a vacuum packaging process a bag or bag is used, the seal (s) along a line between the floor and the mouth connecting the two side edges and with the closed bottom of the bag or bag and one Part of the margins defines a closed, airtight area, with the closed floor also includes another seal, different from the closed one Floor extends inwards into the closed, airtight area, from the two edges, so by gas that exists in the airtight area, during heat treatment be formed, one to the rear and one pulled forward can to open the pack.

The Gas present in the airtight area can also cause shrinkage reduce the thermoplastic film in the area.

drawings

at the drawings attached to it and part of it Forming revelation are:

1 a plan view of a shrink bag according to a specific embodiment of the present invention, wherein the arrow indicates the product loading direction.

2 a perspective view showing the bag with the edges, the arrows indicate how to pull the two edges to open the bag.

The The following reference numerals are used in the figures.

1

bag or bag

2

closed Bottom of the pack

3

first Side edge of the pack

4

second Side edge of the pack

3 '

Part of the page border, with 4 ' . 5 and 6 the closed airtight area 7 Are defined

4 '

Part of the page border, with 3 ' . 5 and 6 the closed airtight area 7 Are defined

5

mouth of the bag

6

second sealing

7

airtight Area

8th

sealing

9

incision

10

margins

11

hole

Similar Reference numerals are used to be similar in the various views or to designate corresponding features.

Summary the invention

With reference to these figures, therefore, a first subject of the present invention is a bag or bag ( 1 of a heat shrinkable thermoplastic gas barrier film for packaging one or more articles, the bag or bag having a closed bottom ( 2 ), two closed margins ( 3 ) and ( 4 ) and an open mouth ( 5 ) for the introduction of the articles to be packaged, the bag or the bag being characterized in that he / she has a seal ( 6 ) along a line between the ground ( 2 ) and the mouth ( 5 ) comprising the two side edges ( 3 ) and ( 4 ), whereby the seal ( 6 ) with the closed bottom ( 2 ) and a part of the margins ( 3 ' ) and ( 4 ' ) a closed, airtight area ( 7 ) and that he / she also has another seal ( 8th ) extending from the closed floor ( 2 ) in the direction of the closed, airtight area ( 7 ) and an incision ( 9 ), which was made in the area passing through the ground ( 2 ) and the seal ( 8th ) is limited.

A special embodiment the present invention is the above-mentioned bag or the above-mentioned bag, where the airtight area also contains a quantity of gas can, so that he can with heat treatment inflates, making two pillow-shaped margins be produced, which have a better appearance of the packaging.

A second object of the present invention is a rupturable, heat-shrunk vacuum pack characterized in that the product is introduced into the aforesaid bag or pouch which is then vacuumized, the mouth ( 5 ) is then sealed and the package is subjected to a heat treatment.

definitions

Of the Term "homopolymer" is referred to herein used on a polymer resulting from the polymerization of a single monomer results, i. a polymer that consists essentially of a single Type of repetitive unit exists.

Of the The term "copolymer" refers to here to polymers produced by the polymerization reaction of at least two different monomers have been formed.

Of the The term "polymer" refers to here both homopolymers and copolymers as defined above.

The Designation "barrier layer" is related here on the ability a film layer uses the permeability of the film for gases such as oxygen and to significantly reduce carbon dioxide. Usually include barrier layers a barrier resin such as PVDC or EVOH.

Of the The term "heat shrinkable" refers to here on slides that have a percentage free shrink of at least Show 15% in at least one direction if they are stuck to a temperature of 120 ° C for 4 seconds according to ASTM D 2732 heated as described in the 1990 Annual Book of ASTM Standards, Volume 08.02, pages 368-371.

detailed description

Even though the invention in conjunction with one or more preferred embodiments It is understood that the invention is not limited to these embodiments limited is. On the contrary closes the invention all alternatives, modifications and equivalents which may fall within the scope of the claims.

With reference to 1 a first subject of the present invention is a bag or a bag ( 1 heat shrinkable thermoplastic gas barrier film for packaging one or more articles, said bag or bag having a closed bottom ( 2 ), two closed margins ( 3 ) and ( 4 ) and an open mouth ( 5 ) for introducing the articles to be packaged, the bag or the bag being characterized in that he / she has a seal ( 6 ) along a line between the ground ( 2 ) and the mouth ( 5 ) comprising the two side edges ( 3 ) and ( 4 ), whereby the seal ( 6 ) with the closed bottom ( 2 ) and a part of the margins ( 3 ' ) and ( 4 ' ) a closed airtight area ( 7 ) and that he / she also has another seal ( 8th ) extending from the closed floor ( 2 ) in the direction of the closed airtight area ( 7 ) and an incision ( 9 ), which was made in the area passing through the ground ( 2 ) and the seal ( 8th ) is limited.

The The film used is a mono- or biaxially oriented, heat-shrinkable Foil.

mono- or biaxially oriented, heat shrinkable Slides are usually made by making polymers from a melt into a thick film extruded or co-extruded, followed by rapid quenching, to prevent or retard crystallization and orient the thick film is by either monoaxially or biaxially under temperature conditions is stretched, in which molecular orientation of the film takes place and the film does not tear. During the subsequent reheating to a temperature near the orientation temperature, it tends to the aspiration to their original one To restore the state of expansion, to shrink. biaxially oriented heat shrinkable Sheets can be used can be obtained by extruding the polymer (s) through a round die or co-extruded, which is a tubular thick film called "ribbon" which results immediately and quickly by means of a water bath or a water cascade usually is quenched to about room temperature. The tape is then at the orientation temperature heated and biaxially stretched at this temperature, e.g. through the so-called "trapped bubble" technique, the one internal gas pressure used to expand the diameter of the belt and to form such a big "bubble" and by the expanded band with a higher one Speed as the extrusion speed is being carried, to get each orientation in cross and machine direction. Usually the stretch is at least about 3 times in each direction. The Foil is then cooled and in the cooled Condition rolled up, so that the property of heat shrinkability preserved. The orientation temperature range generally depends on the type of polymers used. For the production of heat-shrinkable Transparency used orientation temperature is lower in any case as the melting temperature of at least one in the film Polymer. Alternatively you can mono or biaxially oriented heat shrinkable Films are obtained by passing the polymers through a flat die in the form a film are extruded and the film after a quenching step is heated to the orientation temperature and stretched. orientation longitudinal is generally achieved by placing the film over at least two rows of draw rolls is guided the second row is running at a higher speed than the first. Crosswise or crosswise orientation will generally performed in a tenter, in which the edges The film can be gripped by clamps, by two endless chains be carried, which run on two tracks, which are in their course remove each other. If biaxially oriented foils are desired, may alternatively be extended sequentially, i. either way first in the longitudinal direction and then in the transverse direction or vice versa, the extension in both Directions take place simultaneously. The stretched film is then cooled and as usual rolled up. Also in case of orientation through a tenter is the stretch usually at least about 3 times in each direction, but higher stretch ratios are also common.

The used films are usually made of a multilayer structure comprising a gas barrier layer comprises, e.g. a layer, the PVDC, EVOH, a poly or copolyamide etc. as known in the art. Of course, other layers can do the same be present to the structure with the necessary thickness and the necessary mechanical Equip features.

It will be apparent to those skilled in the art that a package may have different shapes, in particular rounded, straight or irregular edges, one or more of which are usually heat sealed. Pouches usually contain one or two factory seals and one or two folded edges: one edge, the open mouth of the pouch, which is adapted to receive an article, is heat sealed after the article has been placed in the bag.

In the "transverse seal bag" (TS bag) machines, the bags are formed by laying a tubing from a thermoplastic film. Thereafter, the film enters an unwind station followed by a hydraulic system for adjusting the size of the bag. This is followed by an impulse seal which closes the margins ( 3 ) and ( 4 ) of the bag and a knife-cutting station which cuts the tube and the mouth ( 5 ) of the bag. The cut, interconnected chain passes through a bag separating station and the formed bags are placed on a conveyor belt and aligned to form a bag chain which can eventually be tied together and packaged. Thereafter, the article is placed in the bags and these are vacuumized, sealed and heat shrunk to complete tight packaging.

Alternatively, the closed margins ( 3 ) and ( 4 ) is formed by a tube material is laid out of a thermoplastic film, and the closed bottom ( 2 ) is formed by heat sealing. In the end seal bag (ES bags) machines, the flattened tape enters an unwind station followed by a pulse seal and a knife-edge station. The formed bags are then arranged and aligned by a mechanical and pneumatic device on a conveyor belt. A tie-down station makes it possible to obtain a collated bag chain.

Bags according to the invention or bags are also made using the horizontal form-fill machines produced. Such packages are made of a heat-shrinkable thermoplastic gas barrier film for packaging one or more several items produced by a longitudinal seal shaped into a tube while at the same time the article to be packaged is introduced into the tube. Thereafter, the tube is hermetically sealed at both ends by two transverse heat seals locked. This type of packs can also be modified under the atmosphere getting produced.

These systems are conventional in themselves and well known in the art. Bags according to the invention are produced according to these or other methods and have a further Siege treatment ( 6 ) along a line between the ground ( 2 ) and the mouth ( 5 ) on which the two margins ( 3 ) and ( 4 ), whereby the seal ( 6 ) with the closed bottom ( 2 ) and a part of the margins ( 3 ' ) and ( 4 ' ) a closed airtight area ( 7 ) Are defined. A seal ( 8th ) extending from the closed floor ( 2 ) inwardly towards the closed airtight area ( 7 ), is prepared before, together with or after the above-described seal. The seal ( 6 ), shown in the attached figures as a straight line, could also be rounded or have any particular shape connecting the side edges of the packaged product. The seal ( 8th ) may have a V or Y or rounded shape, preferably it has a V-shape and is preferably as in 1 shown equidistant from both side edges to form two separate edges upon heat treatment. By pulling one edge forwards and the other back, the packaging opens slightly.

The seal ( 6 ) can be prepared on preformed pouches by means of a device or kit capable of simultaneously sealing ( 6 ) and the tear-seal ( 8th ) to build. The seal ( 6 ) is preferably an impulse seal.

Before, during or after the seal ( 8th ), an incision ( 9 ) in the area passing through the ground ( 2 ) and the seal ( 8th ) is limited. This incision ( 9 ) can also be jagged. The packaging starts from this incision ( 9 ) to tear. This incision ( 9 ) so that he is on the ground ( 2 ) of the bag begins and extends to the seal ( 8th ) extends itself.

In another preferred embodiment of the invention, the incision ( 9 ) in the form of a hole ( 11 ) in which the ground ( 2 ) and the seal ( 8th ) limited area is inserted. The hole ( 11 ) may be useful for suspending the package and may at the same time be shaped to initiate the opening of the package from it, rather than the incision ( 9 ) to use. Alternatively, the hole ( 11 ) in addition to and next to the incision ( 9 ) are formed.

The seal ( 6 ), the seal ( 8th ) and the incision ( 9 ) can also be formed during bag making.

Inventive shrink bag can also printed or dyed be.

In a special embodiment of the invention Shrink bag according to the invention also printed or drawn arrows or drawings to to display how the edges are too pull to open the packaging.

In a specific embodiment of the invention, no gas is produced during bag making blown into the bag or the bag, but through the seals ( 6 ) and ( 8th ) formed two edges and the incision ( 9 ) ensure good tearability of the packaging.

According to the invention contains the airtight Area a lot of gas so that it inflates during heat treatment and thereby two pillow-shaped margins forms, which makes the packaging easier to tear and tear to provide a better appearance of the packaging. That in the airtight Area existing gas can also shrink the thermoplastic Reduce the film in this area.

In 2 the two pillow-shaped edges become ( 10 ) designated. To achieve this effect, the airtight area ( 7 ), an amount of gas preferably between about 0.1 cm ^3/1 cm ² airtight surface to about 0.5 cm ^3/1 cm ² .

at a smaller amount of gas will make the appearance of the package worse be because the two edges have no pillow shape. If in the airtight area a higher amount is contained in gas, the packaging, in particular during the Shrinking, but also while of stacking bags, tear.

The tearability according to the specific embodiment of the invention is obtained in TS and ES bags by introducing a gas, usually air, into the bag. In a specific embodiment of the invention, the gas can be introduced into the bag during pouch manufacture after the seal ( 8th ) has been produced. Then the seal ( 6 ) educated. In another specific embodiment of the invention, first the seal ( 6 ) and then the incision ( 9 ), the gas, usually air, can be removed from the incision ( 9 ) and then the seal ( 8th ) educated. In another specific embodiment of the invention, the gas may be introduced through the incision after it has been made. After that, the seals ( 6 ) and ( 8th ) formed simultaneously or successively.

The Gas can by means of a small nozzle or by means of a blower or by means of suction pads attached to the sides of the bag, wherein the vacuum formed by the Saugpads the separation of the bag sides and the introduction of gas between them causes. The contribution Gas can also be assisted by a roller.

The tearability according to the specific embodiment of the invention is achieved in bags formed with the form-fill-seal machine by applying the seals ( 6 ) and ( 8th ) and the incision ( 9 ) are produced simultaneously or sequentially with the seal closing the packages during the filling of the product. In this type of packaging, which are formed by a thermoplastic film formed into a tube, the seal contained by the seals ( 6 ) and ( 8th ) and the margins ( 3 ' ) and ( 4 ' ), airtight regions already contain a sufficient amount of gas to form two pillow-shaped edges upon heat treatment, and therefore there is no need to inject additional gas.

A second aspect of the present invention is a tearable heat shrinkable vacuum package characterized in that a product is placed in a pouch or pouch of the invention, the pouch or pouch is then vacuumized, the mouth ( 5 ) and the package is subjected to a heat treatment.

Other Methods of making bags and packages are known and can be easy adapted for use.

These This invention may be used in conjunction with all currently available packaging devices become.

The The following examples serve to illustrate the invention, but not limited to that is.

Examples

Around identical conditions for to have the comparison of the behavior of the different samples The chemical compositions of the pouches were formed Retain slide identically.

It Various samples were made to shrink bags without tearability and shrink bags to compare with the new tearing system. The Samples were examined by 44 testers from the point of view of appearance and the functionality rated.

• A. Schrumpfbeutel ohne Aufreißsystem
• B. Schrumpfbeutel mit dem erfindungsgemäßen Aufreißsystem, erhalten ohne Einblasen von Gas in den luftdichten Bereich.
• C. Schrumpfbeutel (1) mit dem erfindungsgemäßen Aufreißsystem und einer Menge an Gas von etwa 0,2 cm³/cm² luftdichter Fläche.

Some items were packed in different bags and presented to the testers:

• A. Shrink bag without tearing system
• As shrink bag with the tearing system according to the invention obtained without blowing gas in the airtight area.
• C. shrink bags ( 1 ) with the tearing system according to the invention and an amount of gas of about 0.2 cm ³ / cm ² airtight surface.

These bags were presented to the testers in random order, using only Their hands were opened and testers were asked to tick their choices. Then, a rating was made for each pack in terms of the ease of opening it. At the end, the testers were asked to indicate which packages were easier to open.

none The tester had difficulty finding out where and how Tear to open from both B and C should be started.

It was not accidentally opened while of the test listed. Overall, a rating results in favor of the EZO system with gas in the two edges (pack C), the one better grip of the edges and easier opening of the Packaging possible; and in particular, they appear to be intentionally made; regarding the Pack C impaired that ripping system is not the general appearance of the packaging, and in most make was the view that this is the appearance of the packaging in the Compared to the conventional ones improved.

The Appearance of the packaging C was rated better by 60% of the testers and from 18% of the testers as comparable to that of the packaging B rated.

Claims (9)

Bag or bag ( 1 thermoplastic film for packaging one or more articles, the bag or bag having a closed bottom ( 2 ), two closed margins ( 3 ) and ( 4 ), an open mouth ( 5 ), a seal ( 6 ) along a line between the ground ( 2 ) and the mouth ( 5 ), which are the two margins ( 3 ) and ( 4 ), whereby the seal ( 6 ) with the closed bottom ( 2 ) and a part of the margins ( 3 ' ) and ( 4 ' ) a closed airtight area ( 7 ), another seal ( 8th ) extending from the closed floor ( 2 ) in the direction of the closed airtight area ( 7 ) and an incision ( 9 ), which was made in the area passing through the ground ( 2 ) and the seal ( 8th ), and the bag or bag is characterized in that the thermoplastic film is a heat-shrinkable and gas-barrier film and that gas in the airtight region ( 7 ) so that it inflates upon heat treatment, creating two pincushion edges. Bag or bag according to claim 1 with an additional hole ( 11 ) in the area passing through the ground ( 2 ) and the seal ( 8th ) is limited. Bag or pouch according to claim 1 with an incision ( 9 ) in the form of a hole ( 11 ) in the area passing through the ground ( 2 ) and the seal ( 8th ) is limited. Bag or bag according to claim 1 formed by laying a thermoplastic film tube flat, the closed side edges ( 3 ) and ( 4 ) have been formed by impulse sealing and the open mouth ( 5 ) has been formed by cutting the tubing with a knife. Bag or pouch according to claim 1, formed by laying a thermoplastic film tube flat, whereby the closed side edges (Fig. 3 ) and ( 4 ) and the closed bottom ( 2 ) has been formed by heat sealing. Bag or pouch according to claim 1, wherein the seal (s) ( 6 ) parallel to the closed bottom ( 2 ) runs. Bag or pouch according to claim 1, wherein the seal (s) ( 8th ) has a V-shape. Bag or bag according to claim 1, wherein the airtight region ( 7 ) contains a gas amount of about 0.1 cm ^3/1 cm ² airtight surface to 0, 5 cm ^3/1 cm ² airtight surface. A method of making a tearable, heat shrunk package comprising: - placing a product in a bag or bag ( 1 ) according to one of the preceding claims, - the bag or bag is vacuumized, - the mouth ( 5 ) the bag or pouch is sealed, and - the closed pouch or the closed pouch is heat treated to shrink the package and the airtight area ( 7 ) inflate.