EP0849071A2 - Method and apparatus for manufacturing a tubular bag package with opening device - Google Patents

Abstract

A method of manufacturing a tubular bag pack (1) uses a horizontal or vertical pouch machine. The pouch comprises either hot- or cold-sealing film. The pack has an opening aid (4) near its longitudinal seam (3). Additional equipment is attached to the packing machine, comprising a stamping unit and control unit. A photocell senses a control point on the packing film, from which the control unit initiates a stamping cycle. The opening aid, a curved gripping tab, is stamped into a non-sealed region outside the longitudinal seam of the pack. Stamping is cyclic, and controlled for precise registration. The tab makes it possible to open the pack across the run of the film.

Description

The present invention relates to a method for producing a tubular bag pack with a die cut on the packaging machine Opening aid that works without tear strips and an opening of the package across to the film direction.

Tear-off aids with tear-off strips that are attached transversely to the film running direction, are known. Mostly, hot-melt-coated tear strips are used used.

DE 2930231 and DE 2635498 describe machine devices or devices for the manufacture of individual packs that make it possible to use tear strips preferably to apply across the film web.

There is a need to equip packs with tear strips with the additional one Demand for tight seams, tear strips that can be sealed on both sides are used made of composite films, with the wrapping material a firm seal enable. However, these are not attached transversely to the film running direction.

Is a cold seal coated due to the temperature sensitivity of the contents Wrapping film used, the back of the film must be equipped with a release varnish be. The structure of the wrapping material requires that a tear strip of the usual type can not or only insufficiently connected to the film. As a result, the seams are not tight in such packs. Only by Introduction of special tear strips, as described in EP 0538768, with lacquer and cold sealant are coated, the seam tightness can be ensured to some extent will.

Often, however, one does without tear strips and uses such packs a serrated cross seal seam or notches in the cross seal seam as tear aids.

With these tearing aids, a pack can only be relatively uncontrolled Tear lengthways and crossways at the same time.

Recently, tear-open aids can also be attached to composite films using lasers (New packaging 6/96 (1996) page 34). A CO2 laser burns certain Targeted layers of composite films without opening the package. An effective opening aid is created by reducing the film thickness. For Installation of this system requires an expensive CO2 laser. Also in CA. 997707 describes a method that uses laser radiation in multilayer Composite films create a line of weakness, which is then used as an opening aid to serve. The system is not suitable for solo films.

A packaging with a tear-off or tear-off, rounded surface section as Handle tab for making an opening for removing paper tissues is described in DE 4416277. This is intended to achieve targeted opening will.

Anfaßzipfel" kann beim Schneide- und Wickelprozeß umknicken und führt durch die hervorgerufene Dickenungleichmäßigkeit zu einem unerwünschten Aufbau von Kolbenringen an den Schnittrollen. iii) Die Stanzvorrichtung für den U-förmigen Anfaßzipfel" muß an der Druck- oder Wickelmaschine fest installiert werden. Sie ist teuer und unflexibel, besonders bei Rapportänderungen des Druckbildes. iiii) Die zusätzliche Stanzvorrichtung stellt ein störendes Aggregat in Druck- oder Schneidemaschinen dar.A tubular bag pack made of cold-seal coated film is known, in which a U-shaped cut is made outside the longitudinal seam. This cut is punched out immediately after printing. This has several drawbacks. i) Films can easily tear or tear during winding and on the packaging machine, especially at high speeds or cycle rates. ii) The U-shaped

Grip tip "can twist during the cutting and winding process and leads to an undesirable build-up of piston rings on the cutting rolls due to the thickness unevenness. Iii) The punching device for the U-shaped Handle "must be permanently installed on the printing or winding machine. It is expensive and inflexible, especially when the repeat of the print image changes. Iiii) The additional punching device is a disruptive unit in printing or cutting machines.

US 4559872, EP 0163808 and CA 1230519 describe small, simple and inexpensive Printing machines described that work with color, which only at higher temperatures fluid and thus printable. These machines are typically used as additional units on packaging machines of the usual type, for example to print the expiry date or other markings.

It was therefore the task of a simple method for producing a Tubular bag pack (1) with a cut or notch (4) in the longitudinal seam (3) to provide an opening of the Packing perpendicular to the direction of film allows and the disadvantages described avoids the manufacture and processing of the film (see FIG. 1).

According to the invention, this was achieved by a method for producing a tubular bag pack on a horizontal or vertical tubular bag machine with a cold or heat sealable packaging film with an opening aid in the area the longitudinal seam, characterized in that by a on the packaging machine attached additional unit, consisting of a punching device and a control device, which means the optical signal of the control point of the packaging film a photo cell in the punching process, an opening aid in the form of a curved Handle tab that opens the tubular pouch in a targeted manner across Film running direction not possible, clockwise and repeatable on one side in the sealed area outside the sealed longitudinal seam of the tubular bag is punched in, and that the longitudinal seam sealing of the tubular bag pack in Area of the handle tab is specifically weakened.

For undefined tearing of the packaging film when opening using a handle To avoid due to too high seal strength, the sealing in the area the handle tab deliberately weakened.

This is done in the case of films coated with cold sealant in that appropriate engraving of the application roller the application weight is reduced. At coextruded heat-sealable films are expediently printed non-sealing varnish in the corresponding sealing area, which partially seals disturbs.

For films that do not have a defined tear propagation behavior, it may be necessary by printing an additional one- or preferably two-component lacquer on the side facing away from the filling material along the desired opening line Support tear behavior. This will keep the packaging film along the desired opening line reinforced.

By converting a small commercial marking device for packaging machines in a punching tool and by adapting the packaging films Surprisingly, a practical method and a device for To provide, which are described by the following claims and which allow the production of a tubular pouch with an opening aid, which does without tear strips to open the package transversely to the To enable film running direction.

For the production of the curved handle tab in the packaging material during the Packing process on the packing machine between unwinding and tube forming station serves a device consisting of two synchronously opposed rollers (7 and 8 in Figure 2), of which a roller (7) a holder for a punching tool (7a) which, at low cycle rates, equipped with a punch, alone punched in required tabs. The roller must rotate 360 ° per cycle. At higher cycle rates, the other bracket (7b) carries an additional one Punching tool, so that the roller, controlled by an electronic control unit, only has to rotate 180 ° per cycle. The other roller (8) serves as a counter-pressure roller and is preferably made of surface hardened steel.

The shape of the punching tools determines the shape of the handle tabs. Preferably becomes a curved shape - semicircular or u-shaped - with a diameter selected from 1-3 cm.

A photocell scans the control point printed on the packaging film and transforms it into an electrical signal which is used by a roller (7) to be set in rotation according to the repetition by means of control unit and motor. The other roller (8) is driven synchronously via gear wheels (9a, 9b). Thereby a punching process is triggered because the packaging film (6) between the two Rolls runs through.

The process according to the invention can be used for olefinic films such as e.g. Polyethylene, Polypropylene (stretched and unstretched) can be used. It is also suitable e.g. for stretched polyamide and polyester films, both as single and can be present as a composite film. The films are said to have low tear resistance have, the tear strength determines the maximum thickness of the film. The ones to be used Foils can be lacquered, metallized, steamed, printed and otherwise be refined.

The subject matter of the invention is illustrated in more detail by the following example explained.

Examples example 1

Foil. On the metallized side of a 30µ thick coextruded, sealable on both sides, Biaxially stretched polypropylene film is used in multicolored rotogravure printing Image printed, which is then provided with a release varnish. The backside This film is partially coated with a cold sealant in the same operation. Figure 3 shows the cold seal coated area (11) on the back a film section (10) which is required for a tubular bag. The areas 12a and 12b are left out when coating with cold sealant. In the area 12a, the curved handle tab is punched out during the packing process. In the area the expected pull tab (13a, 13b) is the order weight by lower Number of cells of the gravure cylinder used in this area reduced.

Packing machine: Fuji Wrapper III horizontal packing machine FW 3400.

Additional unit: Converted embossing unit from Markem type 984 HD, in which the roller carrying the printing type was replaced by a roller with a punching knife was - the ink-carrying roller is dispensed with - and with an additional surface-hardened Steel roller, the roller carrying the punching knife by means of gears is driven.

Method. On the packaging machine, there is a difference between film processing and the format shoulder the additional unit attached. The packaging machine runs with one Cycle rate of 80 cycles per minute and produces tubular bag packs. The Packs are fin packs with plunged back seams.

Example 2

Foil: On the metallized side of a 30µ thick coextruded, sealable on both sides, Biaxially stretched polypropylene film is used in multicolored rotogravure printing Image printed, which is then provided with a release varnish. The backside This film is partially coated with a cold sealant in the same operation coated. Figure 3 shows the cold seal coated area (11) on the back a film section (10) which is required for a tubular bag. The areas 12a and 12b are left out when coating with cold sealant. In the area 12a, the curved handle tab is punched out during the packing process. In the area the expected pull tab (13a, 13b) is the order weight by lower Number of cells of the gravure cylinder used in this area reduced.

Packing machine: Fuji Wrapper III horizontal packing machine FW 3400.

Additional unit: Converted embossing unit from Markem type 984 HD, in which the printing type carrying roller through a roller with two die cutters, which in one 180 ° to each other, was replaced - on the inking roller is dispensed with and with an additional surface hardened steel roller by the roller carrying the punching knife is driven by means of gear wheels.

Process: On the packaging machine, there is a difference between the film processing and the format shoulder the additional unit attached. The packaging machine runs with one Cycle rate of 250 cycles per minute and produces tubular bag packs. The Packs are fin packs with plunged back seams.

Example 3

Foil: On the metallized side of a 20µ thick coextruded, sealable on both sides, Biaxially stretched polypropylene film is used in multicolored rotogravure printing Image printed, along the opening line (17 Fig. 4) is a two-component Lacquer applied and finally the entire print is provided with a release lacquer. The back of this film is partially in the same operation with a Cold sealant coated. Figure 4 shows the cold seal coated area (15) the back of a film section (14) required for a tubular bag becomes. The areas 16a and 16b are coated with cold sealant recessed. In area 16a, the bent handle tab is used during the packing process punched. The application weight of the cold sealant is in the areas 18a and 18b reduced.

Packing machine: Fuji Wrapper III horizontal packing machine FW 3400.

Additional unit: Converted embossing unit from Markem type 984 HD, in which the roller carrying the printing type was replaced by a roller with a punching knife was - the ink-carrying roller is dispensed with - and with an additional one surface hardened steel roller, by means of the roller carrying the punching knife Gears are driven.

Process: On the packaging machine, there is a difference between the film processing and the format shoulder the additional unit attached. The packaging machine runs with one Cycle rate of 80 cycles per minute and produces tubular bag packs. The Packs are fin packs with plunged back seams.

Example 4

Foil: A 32µ thick, biaxially stretched polypropylene film, acrylic lacquered on both sides (Bicor 32MB600 from Fa Mobil) is on the side facing away from the product multicolored rotogravure printing. The back of this film is partially in the Area of the expected handle tab (22a, 22b in FIG. 5) with a not sealing varnish printed to reduce the sealing strength somewhat.

Packing machine: Fuji Wrapper III horizontal packing machine FW 3400.

Additional unit: Converted embossing unit from Markem type 984 HD, in which the roller carrying the printing type was replaced by a roller with a punching knife was - the ink-carrying roller is dispensed with - and with an additional surface-hardened Steel roller by means of the roller carrying the punching knife Gears are driven.

Process: On the packaging machine, there is a difference between film processing and Format shoulder attached to the additional unit. The packaging machine runs with it with a cycle rate of 80 cycles per minute and produces tubular bag packs. The packs are fin packs with plunged back seams.

Comparative Example 1

Film: Composite film made of counter-printed biaxially stretched polyester film (PETP) with a coextruded, sealable and one-sided metallized biaxially stretched polypropylene film.

Tear strips: composite film made of two 20µ thick sealable biaxially stretched polypropylene films, which is provided with an interlayer print.

Packing machine: Horizontal tubular bag machine.

Method: A tear strip is applied transversely to the film running direction according to DE 2635498 on the packaging machine between the film processing and the format shoulder. The packaging machine runs at a cycle rate of 200 cycles per minute. The packs are fin packs with plunged back seams. Summary of examples and comparative examples E.g. foil Packaging machine Additional unit method 1 printed 30µ thick metallized BOPP film with KS backing, partially lower application weight horizontal form, fill and seal machine 1 punch knife 80 Tkt / min 2nd printed 30µ thick metallized BOPP film with KS backing, partially lower application weight horizontal form, fill and seal machine 2 punch knives 250 Tkt / min 3rd printed 20µ thick metallized BOPP film with additional pressure along the opening line u. with KS equipment on the back, partially lower order weight horizontal form, fill and seal machine 1 punch knife 80 Tkt / min 4th printed 32µ thick acrylic lacquered BOPP film on both sides. Partially non-sealing varnish horizontal form, fill and seal machine 1 punch knife 80 Tkt / min V1 Composite film made of PETP and BOPP; additional tear strip horizontal form, fill and seal machine 200 Tkt / min

Claims (5)

Process for the production of a tubular bag package on a horizontal or vertical form fill and seal machine with a cold or heat sealable Packaging film, with an opening aid in the area of the longitudinal seam, thereby characterized in that by an attached to the packaging machine Additional unit, consisting of a punching device and a control device, which is the optical signal of the control point of the packaging film converted into the punching process by means of a photocell, an opening aid in Form of a curved handle tab, which allows a targeted opening of the tubular bag pack made possible transversely to the film running direction, cyclically and according to repeat one-sided in the unsealed area outside the sealed area Longitudinal seam of the tubular bag is punched and that the longitudinal seam seal the tubular pouch in the area of the grip tab is weakened. A method according to claim 1, characterized in that the weakening of the Sealing of a cold-seal coated film due to lower application weight of the cold sealant. A method according to claim 1, characterized in that the weakening of the Sealing a heat sealable film by partial pressure of a unsealing lacquer. A method according to claim 1, characterized in that the packaging film carries a reinforcing lacquer along the desired opening line. Device for producing a curved handle tab, consisting of two synchronously opposed rollers (7 and 8), one roller (7) Holders for one or more punching tools (7a, 7b), in which after Need one or more punching tools to be attached and another Roller (8), which serves as a counter-pressure roller and preferably made of surface hardened Steel exists, in addition, the one roller (7) over a Motor that is controlled by the control unit, which by means of a Control points of the packaging film-recognizing photocell a drive pulse relates, drive and the other roller (8) via gears (9a, 9b) drives synchronously, between which the packaging film (6) runs.

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