EP1584448A1 - Sealing device for applying a plastic foil on a substrate material. - Google Patents

Abstract

A sealing unit (8) comprises a sealing plate (11) with heated active surface and back plate (9), die cutting unit (16) with die cutting knife (15), and counter plate for making die cuts at selected locations in the planar substrate material in the region of the applied plastic foil. The sealing plate has set(s) of raised and depressed regions on its active surface. A sealing unit comprises a sealing plate with heated active surface and back plate, die cutting unit with die cutting knife, and counter plate for making die cuts at selected locations in the planar substrate material (1) in the region of the applied plastic foil (7). The sealing plate generates heat and pressure to the substrate material during the sealing process. It has set(s) of raised regions (14) and depressed regions (13) on its active surface facing the back plate and the location of the depressed regions in the sealing plate corresponds to the location of the die cutting knife, so that cut is made at the selected positions in the substrate material where, because of the depressed regions of the sealing plate, there is reduced heating of the substrate material and associated laminations.

Description

The invention relates to a sealing unit for applying a plastic film to a flat substrate material by means of heat and pressure with a sealing plate with active surface and a relative to this movable counter-jaws, wherein the sealing unit is a punching unit with punching knife and counter plate for the subsequent introduction of punch cuts at selected locations in the planar substrate material is connected downstream in the region of the applied plastic film.

Sealing units of the aforementioned type are known in the practice of packaging manufacturers. In one example, a filling machine is for making and filling a liquid package known from a tube of packing material continuously under filling and closing will be produced. The packing material in this known example is a plastic-coated, flat carrier material, paper or cardboard is used as a carrier material. Opening devices of these known packages consist of a hole through the surface Substrate material, with the hole on the inside of the pack with a plastic film and on the outside is closed with a tear tab. Tear tab and plastic film are together welded so that when tearing the tear tab to open the pack of the area within the punched hole of the inner plastic film to form the pouring opening being torn out with.

Previously, you had the pull tab on the outer plastic film of the pack directly over the hole welded. It has then proved to be a disadvantage when tearing open the tear tab that the outer plastic film was stained with demolished so that outside partially coated, printed cardboard, partly the bare cardboard and partially plastic nets saw the created a poor mouthfeel for the end user when putting the pack on to drink.

Therefore, one has already gone over to another plastic film in the area of the later Surround the hole with a gap, seal it on the outer plastic layer of the package. In this plastic film or plastic film prepatch in English-speaking professional circles is called, it is a so-called OPP film, which is transparent and pakkungsseitig Apply well to the plastic layer resting on the substrate leaves and connects with this well, while she outwardly peel to the pull-tab weak connection forces developed, especially if the tear tab with a Polyethylene (PE) coated aluminum is. The flat substrate material is together with this applied plastic or prepatch film punched out of OPP film. After that, the tear tab removed to open the pack, then arise no longer the spot-shaped small areas with bare cardboard, coated cardboard and plastic nets. Much more Now results from the application of this prepatch plastic film, this plastic or cut-out for the end user, if he drinks the liquid from the pack, a good one Mouthfeel.

In the manufacture of such packages with this type of sheet substrate material is a sealing unit of the type mentioned above to the stain or the plastic film on the later aufzusiegeln later outside of the substrate material, after which immediately described Punching the entire substrate material to form the Ausgießloches takes place. Therefore the sealing unit is followed by a punching unit, in which a correspondingly shaped Punching knife through the entire substrate material with the various plastic layers and Foils is pushed through.

In this punching process now arises in the prior art, a problem in that the Substrate material brought in the sealing unit for applying the plastic film to sealing temperature and shortly thereafter the selected location for the punching cut led into the punching unit is, so that the punching knife by a still close to sealing temperature befindliches substrate material must push through. At a disadvantage fringe the cutting lines, which by the punching knife produced, more or less strong, and it remains here and there mere plastic or Scrap cardboard or fibers like scraps. Sealed so poorly cut Openings with a pull-tab, then arise here and there leaks and unusable Packages with leakage. For a larger collection of packs suffice one to three leaking packages, around the entire collection container useless and unsalable close. It has therefore made a variety of attempts, these frays next to avoid the punching knives. So you have, for example found that a punch with circular Knife in very hot new condition produces clean cuts for a while. After 150 hours of operation, the punching knife was so fuzzy and worn that again the fraying resulted. With further disadvantage, the protruding rags, fringes accumulate and snippets in the discharge chute of the machine, resulting in blockages. The frequent Replacement of punching tools poses a further disadvantage for the pack manufacturer unbearable cost increase.

The invention is therefore based on the object, the sealing unit of the type described above to improve so that no more fibers on the punch cuts, neither from the substrate still being torn out of the plastic, but creating clean cuts without any protrusions.

The solution of this object succeeds according to the invention in that the sealing plate of the sealing unit has raised and recessed areas on its active, counter-jaw-facing surface and the position of the recessed areas in the sealing plate corresponds to the position of the punching knife (s), so that the punched cut comes to rest there in the substrate material at the selected locations, where due to the recessed areas of the sealing plate almost no heating of the substrate material with his coatings. One must first assume that with the specially designed Sealing plate with the raised and recessed areas in the active surface of the Plastic film is sealed in a larger surface area of the substrate material, where Subsequently, in the punching unit punched cuts are to be inserted, and around them. These Die cuts succeed with particularly good quality, i. as sharp cuts without fraying, when the punch blade is driven through cooler areas of the substrate material. If now by appropriately skillful design of the sealing plate in a specific location on selected Provide in-depth areas to be provided in the subsequent step in the Punching unit are offered to the cutting process, then the punching knife in areas of the Substrate material penetrate, which were not brought to a higher temperature, as in other (raised) areas for the application of the plastic film itself is necessary. The Plastic film can therefore be applied with useful adhesion to the substrate material, wherein (through the recessed areas in the sealing plate) produces cooler areas at selected locations be, because just because of the recessed areas of the sealing plate there almost no warming took place. Surprisingly, it has been shown that punch cuts made in this way sharp and without fraying could be made even if the cutting blade many operating hours were in operation. One is through the thus configured sealing plate with the recessed Areas surprisingly able to cuts without supernatants even with coated substrate material to create.

In a further advantageous embodiment of the invention, it is provided that at a predetermined distance arranged in the conveying direction of the substrate material behind the sealing unit, the punching unit and coordinated control of both units is such that the selected locations in the substrate material in the sealing unit over the recessed areas and then in the punching unit to be under the punching knife (s). The sealing unit and the punching unit can be two separate devices arranged one behind the other in the manner described above are that the substrate material, whether it is now arcuate or web-shaped, first in the sealing unit and then fed into the punching unit. The time that elapses to the substrate material from the sealing unit to the punching unit amounts to between one second and three Minutes and is preferably two seconds. It is essential that the substrate material in The sealing unit is heated to sealing temperature, that is about 160 ° C, and that after the the time the substrate material has been processed, while still being processed in the punching unit a relatively high temperature such that the plastic layer or layers or relatively high temperature has such that the plastic layer or layers or films or movies are still relatively soft. For then there would be those described above Fraying, would not use the inventively designed seal plate.

When it is said that the substrate material in the sealing unit over the recessed areas and then in the punching unit under the punching knife, then here is with "over" and "under" meant less a local direction, but the position for the intervention (with appropriate Effect) of the recessed areas on the one hand and the punching knife on the other hand on the substrate material. In a preferred embodiment, however, the substrate material also comes locally lie over the recessed areas, i. the sealing plate approaches the substrate material of down and push it up against the counter-jaw. In this or another preferred Embodiment preferably comes in the punching unit, the substrate material under the or the punching blades to lie, i. the punch blade moves from above the substrate material through this down a bit to reach the punching. For others Machines could also be other directions of movement of the sealing plate and the punching knife be cheap.

Whether the sealing unit is a separate device from the punching unit, both have to Units are controlled in a coordinated manner, so that the substrate material at the selected locations is spared against an increase in temperature and the or the punching knife only in these cold work remaining areas, because it should be avoided that a punching knife in a substrate material penetrates with high temperature. Therefore, the coordinated control of the units primarily local, hence the position of the punching knife to the cold remained areas is properly aligned in the substrate material. Only secondarily, it is in the coordinated control by a temporal influence. Preferred machines in practice but contain both units in a processing line, in which a web-shaped, planar Substrate material is advanced intermittently, first in the sealing unit and then in the punching unit. Just because of the space in the machine, the two units relatively close to each other, it also follows that the time between the stay in the sealing unit is too short to stay in the punching unit, as that increased by the sealing plate Temperature of the substrate material is substantially cooled from one unit to another.

According to the invention it is further provided that the recessed areas in the active surface the sealing plate form a pattern which is an illustration of the pattern of the punching knife (s) of the Punching unit on the same scale, so that both patterns are congruent. The sealing plate acts in this way as a stencil, which on the substrate material a temperature pattern like generates a thermal image. This pattern of recessed areas of the seal plate is true substantially the same position as the punching knife (s) - with one exception, which will be explained below. By this coincidence and congruence of the patterns in The two units ensure that the punching knife - in what shape, position or arrangement however, the substrate material is only punched in the cool areas. Thereby are avoided with advantage the fraying, so that it is not in the punching unit of the machine mentioned in the beginning disadvantageous blockages.

The exception mentioned above is that a punching knife and also its effect (the section) are considerably narrower than the groove-like depressions or recesses in the Sealing plate. The invention is further characterized in that the recessed portion of the Sealing plate is wider than the punching knife of the punch, and the punched cuts of the punching pattern encompasses all sides. In compliance with this condition, it is ensured that the punching knife or the Punching tool cuts only in cold areas of the substrate material and no fraying anywhere is to be feared.

If, in a further advantageous embodiment of the invention, the sealing plate consists of metal and is milled on its active surface to form the recessed areas, preferably the active surface is coated with an abrasion-resistant plastic material, the sealing unit can be and in particular to make the sealing plate simple, inexpensive and effective. It has proved to be particularly favorable to use as metal for the sealing plate aluminum. The deepened Areas then give a particular pattern of grooves, with the raised areas of course formed by the remaining material (e.g., aluminum).

For a favorable sealing, the active surface of the sealing plate is preferably with the mentioned coated abrasion-resistant plastic material, which is in advantageous embodiments Teflon. After application of heat and pressure by means of the sealing plate then dissolves their active surface easier again from the plastic film, i. the clipping or the attached outer patch.

The substrate material may be any at least partially plastic coated substrate be, e.g. Cardboard or paper. The problem with fraying or punching with fibers arises whenever a plastic film on a substrate at a temperature in the Range of softening temperature of the plastic to be punched. In the substrate material it may be plate or arcuate parts.

However, it is particularly preferred according to the invention if the flat substrate material is in web form is intermittently movable by drive means from the sealing unit into the punching unit. Such Device in which both units are combined, is particularly useful Used as an opening unit for a filling machine, this opening unit is provided in the conveying direction of the web-shaped substrate material in front of the filling machine.

So it has, for example According to the invention proved to be favorable when the sealing unit to an opening unit belongs to a liquid filling machine and the substrate material a carrier sheet provided with a plurality of plastic layers with score lines for production a pack with pull tab and the pattern of the punching knife is a circle. They are liquid packs in the form of a cuboid well known. It is also known, such To produce liquid packages of plastic-coated cardboard as a substrate material, from the cardboard web, which is moved intermittently through the filling machine, ultimately filled and sealed pack is carried away. This pack also has a pouring spout, which consists of a hole inserted in the topsoil of the pack, which from above, the later Outside of the pack, is closed by a pull tab and preferably by is sealed inside by another plastic film (edge protection of the cutting lines).

An upstream paper machine produces the web with the package blanks, these being Web of the packaging material as a carrier has the mentioned cardboard, preferably with a plurality of Layers is covered. This includes e.g. an aluminum layer and polyethylene layers applied to it. Before sealing the tear tab on the outside and the plastic film (Polyethylene) on the inside of the later pack on the hole, so before those last two Coatings done, is provided with the various coatings substrate sheet punched to form the hole, and in a circular hole is then the Pattern of the punching knife corresponding to a circle. The coated substrate sheet is also with various, known "score lines" provided to from the filled with the liquid content and then sealed by sealing tube to form the packs by folding. In These packing manufacturing and filling machines came the aforementioned problem of leakage for years, without a tool-wise solution could offer. Only the invention with the specially designed sealing plate and the recessed areas, with their Helping the cutting areas to be left cold has the problems to the fullest satisfaction solved. It can now liquid packs in large quantities per unit of time with powerful Filling machines are manufactured and summarized in collection batches without getting even just a package with leakage shows.

Figur 1

die Draufsicht auf ein abgebrochenes Stück eines bahnförmigen Substratmaterials in Form einer mit Kunststoff beschichteten Kartonbahn nach Anbringung des äußeren Kunststofffleckens auf herkömmliche Weise mit nachfolgendem Ausstanzen eines Loches,

Figur 2

in einer Querschnittsansicht links die Siegeleinheit und rechts die Stanzeinheit vor dem Stanzen bei einer erfindungsgemäßen Ausführungsform,

Figur 3

in gleicher Querschnittsansicht wie Figur 2 die Stanzeinheit kurz nach dem Stanzen des Loches,

Figur 4

eine ähnliche Ansicht wie Figur 1, hier jedoch mit dem erfindungsgemäß hergestellten Produkt, bei welchem der von oben auf die beschichtete Kartonbahn aufgebrachte äußere Kunststoffflecken um das in der Mitte ausgestanzte Loch herum einen siegelfreien Ringbereich hat, und

Figur 5

eine Querschnittsansicht eines bevorzugten Substratmaterials mit gestrichelt gezeigter Stanzlinie und schematisch dazwischen angeordneter Linie zur Veranschaulichung, daß die äußeren Schichten miteinander versiegelt sind.

Further advantages, features and applications of the invention will become apparent from the following description of a preferred embodiment in conjunction with the accompanying drawings. In these show:

FIG. 1

the top view of a broken piece of a web-shaped substrate material in the form of a plastic-coated board web after attachment of the outer plastic spill in a conventional manner with subsequent punching a hole,

FIG. 2

in a cross-sectional view on the left the sealing unit and on the right the punching unit before punching in an embodiment according to the invention,

FIG. 3

in the same cross-sectional view as Figure 2, the punching unit shortly after punching the hole,

FIG. 4

a view similar to Figure 1, but here with the product according to the invention, in which the applied from the top of the coated board web outer plastic patch around the hole punched in the middle has a seal-free ring area, and

FIG. 5

a cross-sectional view of a preferred substrate material with a broken line shown in phantom and schematically arranged therebetween line to illustrate that the outer layers are sealed together.

Figure 1 shows the view of a broken piece of a web-shaped carrier material or substrate material 1. The web of this material 1 is in the conveying direction 2 in Figures 1 to 4 of promoted intermittently to the left to the right. With 3 two score lines are indicated, which are transverse to the Conveying direction 2 of the substrate material and a part of the blank of the subsequent packaging represent. In this schematic representation of the figures is intended by the two score lines 3, the top wall 4 of the package are formed, in the later the opening device and so that the hole 5 are arranged. The pouring hole 5 is obtained by introducing the punched cut 6 in the substrate material. In FIG. 5, the punched cut 6 is indicated by the two dashed lines which differs through the coated substrate material but not through the two go through outer layers.

However, the punched cut 6 also passes through the externally applied patches of the plastic film 7 therethrough. In this case, the outside of the later beverage package of this particular embodiment to think in the direction of the viewer on the figures above the substrate material 1 and in the cross-sectional view of the substrate material 1 of Figure 5 below; the inside So in the figures 2, 3 and 5 above and in the plan view of Figures 1 and 2 behind the aborted Share. In a only in Figure 2 generally denoted by 8 sealing unit is the stained Plastic film 7 sealed before punching out of the hole 5, but in the example 1 in a conventional manner, in which a sealing plate, not shown, with smoother planar surface is shown as well as the counter-jaw 9 of the sealing unit 8 in This has the consequence that the entire hatched in Figure 1 area of the plastic film. 7 brought by the sealing to the softening temperature and the punching cut 6 (in in FIG 1, not shown) frayed and provided with fibrous supernatants. In the conventional Thus, hole 5 can repeatedly cause leaks in the area of the pouring opening come. If you ignore the non-hatched area of the hole 5 in Figure 1 can be seen, one recognizes the square sealing surface 10, which is practically below the entire plastic film 7 is located.

In order to avoid the disadvantages associated therewith, that in FIG Substrate material 1 arranged sealing plate 11, which supported according to arrow 12 from below, stored and fixed, groove-like recessed areas 13 and adjacent raised areas 14. You go assume that the raised areas 14 are formed by standing during the milling process, then you can in the production of the sealing plate at selected locations, the recessed areas 13 mill out with the desired width to form a pattern. The width of the recessed areas 13 is about 2 to 20 mm, preferably 5 to 15 mm, and the recess creates a height difference from 0.5 to 4 mm, preferably 1.5 to 3 mm and most preferably 2 mm. The teflon coating is then so applied that it affects both the sublime and the recessed areas 13, 14 is, as shown in Figure 2 but not shown. In the case of a pouring hole 5, the line of the punched cut 6 runs approximately after a circle, so that the pattern of a Circle results. This circular pattern is not only followed by the punching knife 15 and thus also the Line of the punched cut 6, but also the recessed areas 13. The web-shaped substrate material 1 extends through both the sealing unit 8 of FIG. 2 and the punching unit 16 through and is continuously moved intermittently in the conveying direction 2. The plastic film 7 in the form of the outer patch is indicated in FIG. 2 by a line in the region of the sealing unit 8 below the Material 1 shown because the plastic film 7 are sealed to the outside of the material 1 should. Now press the movable counter-jaw 9 on the sealing plate 11 with inserted in between Substrate material 1 with plastic film 7, then heat the gray applied areas in the material 1, because these are the raised areas 14 of the sealing plate 11 opposite. In between, the cold regions 17 result in the path of the substrate material 1.

If one transfers this idea to the representation of Figure 4, then one recognizes an almost circular one Ring area with a hatching from top left to bottom right, which is the cold area 17 represents. However, it should be noted that before punching the hole 5 of this cold region 17 also extends a little way inwards beyond the punched cut line 6, because the punching cut 6 must be completely surrounded on both sides by cold areas 17.

In the illustration of Figure 2, this is clearly seen that the cold areas 17 in the web-shaped substrate material 1 almost centrally located under the punching knife 15. Will that be in this Embodiment designed as a stamp punching knife 15 in the direction of arrow 18 after moved down through the substrate material 1, then not only the punching cut 6 is placed, but you can see the hot seal area 19 of the punched disc 20 with the Close adhering plastic film 7, and laterally next to the two outer punch cuts 6 again the white cold regions 17 shown in Figure 3 in the substrate 1 at. On So both parts of the punched section 6 are parts of the cold areas 17 with the result that the Punch cut 6 was passed completely through cold material. This achieves the fiber-free and fringe-free, clean diecut 6 in the desired pattern, shown here Embodiment approximately in the form of a circle.

In FIG. 3, the punch with the punching knife 15 is then in the opposite direction to the movement arrow 18 again pulled up, and it is then shown in Figure 4 in plan view Condition before.

It is understood that the counter-plate 21 of the punching unit 16 at selected locations, the circular Has limitation of the hole to the punching blade 15 a shearing action for punching to reach the hole 5.

The distance in the conveying direction 2 of the punching unit 16 from the sealing unit 8 results according to FIG 2 from the vertical distance of the arrows 9 and 18, which are approximately in the respective center line of the unit lie.

FIG. 5 schematically shows a broken cross-section through the generally designated 1 Substrate material. The substrate sheet 22 in this embodiment is a board web and as a relatively thick web about in the middle with a hatching from top left to shown at the bottom right. Down from this middle panel 22, the outer layers are laid up, up the inner layers, considering the later packaging. An aluminum layer 23 is placed on the inside and an aluminized layer 24 on the outside, both by a cross hatching are shown. Outward then follows the print layer 25 with a hatching two phase-shifted sinusoidal lines. It is known, packaging externally to be provided with a pressure, and if this on an aluminised Layer 24 in the form of the pressure layer 25 applies, then you can as in this particular embodiment achieve a gloss effect. For protection is then outside of the print layer 25 and inside of the aluminum layer 23 each applied a plastic layer, preferably made of Polyethylene (PE). This is designated on both sides with 26 and practically not with a hatching Mistake.

Up to this PE layer 26 is the web-shaped substrate material 1. This is then in the sealing unit 8, the patchy plastic film 7 using the special sealing plate 14 sealed. The aufgesiegelte state is shown in Figure 5, and this plastic film 7 is with short short hatching from top left to bottom right marked.

In this condition, i. Substrate material 1 plus plastic film 7, the punching is done so that the punched section 6 shown as dashed lines results. The said substrate material with the Plastic patches 7 now has a hole which will later be used as a pouring hole 5 can. But first, the pack must be tight. For this purpose, a tear strip 27 is sealed from the outside, which shows a hatching from bottom left to top right in FIG. It is at this Tear tab 27 around polyethylene coated aluminum, as is known per se. On the opposite inside, in the illustration of Figure 5 so above, is another polyethylene layer Sealed over the hole and sealed with the pull tab 27. The latter Bonding by sealing between the inner polyethylene layer 28 and the outer pull tab 27 is shown in Figure 5 by a solid line 29 with two end points. That is, the end user tears open the tear tab 27 from the filled beverage package, then it also ruptures the inner polyethylene layer 28 in the region of the pouring hole 5 to access to get to the package contents and to use the pouring hole 5 can. The inner one Polyethylene layer 28 is by a hatching with alternating lines from the bottom left to marked top right and intermediate points.

Claims (7)

Sealing unit (8) for applying a plastic film (7) to a sheet-like substrate material (1) by means of heat and pressure with a sealing plate (11) having an active surface and a relative to this movable counter-jaw (9), wherein the sealing unit (8) is a punching unit (16) with punching knife (15) and counter-plate (21) for subsequent introduction of punched cuts (6) at selected locations in the sheet-like substrate material (1) in the region of the applied plastic film (7) is connected downstream,
characterized in that the sealing plate (11) of the sealing unit (8) on its active, the counterjaw (9) facing surface raised (14) and recessed areas (13) and the position of the recessed areas (13) in the sealing plate (11 ) corresponds to the position of the punching blade (s) (15), so that the punching cut (s) (6) comes to rest at the selected locations in the substrate material (1) where, due to the recessed areas (13) of the sealing plate (11) there was almost no heating of the substrate material (1) with its coatings. Sealing unit (8) according to claim 1, characterized in that at a predetermined distance in the conveying direction (2) of the substrate material (1) behind the sealing unit (8), the punching unit (16) is arranged and a coordinated control of both units (8, 16) in that the selected locations in the substrate material (1) in the sealing unit (8) come to lie below the recessed areas (13) and then in the punching unit (16) under the punching knife (15). Sealing unit (8) according to claim 1 or 2, characterized in that the recessed areas (13) in the active surface of the sealing plate (11) form a pattern which is a representation of the pattern of the punching knife (s) (15) of the punching unit (15). 16) is the same scale, so that both patterns are congruent. Sealing unit (8) according to one of claims 1 to 3, characterized in that the recessed area (13) of the sealing plate (11) is wider than the punching knife (15) of the punch and the punched cuts (6) of the punching pattern surrounds on all sides. Sealing unit (8) according to one of claims 1 to 4, characterized in that the sealing plate (11) consists of metal and is milled on its active surface to form the recessed areas (13), wherein preferably the active surface coated with an abrasion-resistant plastic material is. Sealing unit (8) according to one of claims 1 to 5, characterized in that the sheet-like substrate material (1) in web form by drive means of the sealing unit (8) in the punching unit (16) is intermittently movable. Sealing unit (8) according to one of claims 1 to 6, characterized in that it belongs to an opening unit for a filling machine for liquid packages and the substrate material (1) provided with a plurality of plastic layers (23, 24, 26) carrier material web (22) with score lines (3) for producing a pull tab package (27) and the pattern of punching knives (15) is a circle.

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