EP0914939B1 - Method of manufacturing flat-bottom bags with a glued-on bottom lining - Google Patents

Abstract

The bag-making process is for a bag with a flat bottom and a stuck-in internal crosspiece. A contact adhesive (34, 52, 54) is used for the internal crosspiece. Its adhesive properties are only effective when two surfaces coated with this adhesive are pressed against each other. The contact adhesive is applied to the bag material before this material is closed to form a tube and before the bottom position is established. Adhesion is then achieved after pressing the internal crosspiece, with contact adhesive applied, to the flat bottom (18).

Description

The invention relates to a method for producing floor bags with glued inner bar.

For bottom bags, for example block bottom or cross bottom bags Paper, plastic film or the like form the bottom flaps on the inside the bag unwanted voids such as crevices or pockets, in to which powdery, granular or pasty remnants of the contents of the bag stick can. It is therefore known inside the bottom of the bag to glue a so-called inner bolt, which is usually by a rectangular sheet is formed from the bag material and all around with the Bottom flaps are glued or welded so that the cavities face each other sealed inside the bag.

A method for producing such bags is known from WO 95/02544, where the bag material as well as the inner bar made of polyethylene on the inside coated paper. After this procedure, the inner bolt on the edges parallel to the narrow edges of the Run the floor, glued to the associated floor tabs, and parallel towards the broad edges of the floor face each other coated surfaces of the inner transom and the bottom flaps through continuous Weld lines welded together.

However, gluing or welding the inner bolt is generally procedural relatively difficult and expensive because of the needed Tools there is no direct access to the inside of the floor. The Weldings are therefore generally carried out on the flat floor, so that there are several layers of material in the soil between the Welding tools. In general, therefore, by an appropriate Process control or through inserted separator sheets or the like be ensured that the weld is targeted only to the desired Places and no material layers welded together are separated from each other later when filling the bag Need to become. Similar problems arise in the case of bonds, because then the glue, usually glue or hot melt glue, while the manufacturing process must be applied so that no undesirable Adhesive spots are created and the bottom flaps are created when the inner bar is attached not to be smeared with glue.

The usual method for the production of floor bags is that the Starting material in the form of an endless web drawn off a roll and then it is first closed to form a tube, which is then cut into suitable lengths is divided to form the individual bags. The so obtained Pieces of tubing are continuously rotating on a rotating drum fed, at which a winding station successively in the circumferential direction, a floor laying station and a closing station are arranged. In the winding station become the top and bottom layers, which lie flat on top of each other the hose at the bottom end pulled apart so that a wide open floor opening. In the floor laying station, the in Opposite edges of this bottom opening pulled apart, and the longitudinal edges are folded over so that bottom flaps are formed, partially overlapping each other and flat on the circumference of the floor laying drum issue. The flaps folded outwards are then in the closing station folded over and glued together by a final glue, so that you get a closed floor.

If the floor is to be provided with an inner bolt, this inner bolt must between the winding station and the floor laying station in the floor opening introduced and then welded or glued to the bottom tabs become. Through the gluing and / or welding equipment required for this the structure of the device is considerably complicated, and since the additional Process steps such as applying the adhesive, making the weld lines and the like take a certain amount of time, the total processing time increases, so that in the continuous manufacturing process only a correspondingly low output of bags can be achieved.

DE-A-25 14 219 describes a method for producing cross-bottom bags known in which for gluing the bottom flaps only on self-adhesive Contact adhesive is used even before the hose is closed is applied to the continuous material. If there is an internal latch in the floor with such a method, there is the problem, however, that the adhesive surfaces provided on the hose for the inner bolt already can glue together prematurely when the hose through the device is transported.

The object of the invention is therefore to provide a method which with a relatively simple system a more rational continuous Manufacture of bags with glued inner bar permitted.

This object is achieved by the one specified in claim 1 Procedure solved.

The inventive method has the advantage that the for gluing the The interior bolt required the adhesive before the hose was closed on the Starting material for the bag can be applied. Because the contact adhesive is not liable unless two surfaces are coated with this contact adhesive can be pressed against each other, unwanted adhesions in the Closing the starting material to a tube and the following Avoid editing. Only after the inner bolt has been put on the corresponding one The adhesive surface is in turn provided with contact adhesive, the Contact adhesive take effect. The inner bars can also be opened before they are fed to the floor-laying drum coated with contact adhesive so that immediately no additional time for the application of the Glue is needed in hard-to-reach places and on the circumference of the floor laying drum also no corresponding order facilities provided will need. When laying and closing the floor come next the associated adhesive surfaces of the Inner bolt and the bag in contact with each other, and there in connection with the closing of the bottom flaps and the final glue usually anyway pressure is exerted on the bottom of the bag, the contact adhesive effective so that the inner latch and the bottom tabs are tightly together be glued without additional measures being required are. In this way, an extremely efficient gluing of the inner latch is enables, and there can be a high output of the bag making machine can be achieved.

The adhesive surfaces coated with contact adhesive on the upper and lower Material layer of the hose are arranged offset against each other, so that they do not immediately after closing and laying the hose come into contact with each other. Therefore, the means of transport can attack the hose without causing premature sticking of the the contact adhesive coated areas.

Advantageous further developments and refinements of the invention are in the Subclaims specified.

Fig. 1

eine perspektivische Ansicht des Bodenbereichs eines Beutels mit Innenriegel unmittelbar vor der Schlußklebung;

Fig. 2

die Anordnung von Klebeflächen auf einem Zuschnitt für den Innenriegel;

Fig. 3

die Anordnung von Klebeflächen auf dem Ausgangsmaterial für den Beutel; und

Fig. 4

eine perspektivische Ansicht des Innenriegels und des Bodenbereichs des Beutels unmittelbar vor dem Anlegen des Innenriegels.

For a more detailed explanation of the invention, reference is made below to the drawings, which, however, do not illustrate the method according to the invention, but rather a somewhat modified method. Show it:

Fig. 1

a perspective view of the bottom portion of a bag with an internal bar immediately before the final glue;

Fig. 2

the arrangement of adhesive surfaces on a blank for the inner bar;

Fig. 3

the arrangement of adhesive surfaces on the starting material for the bag; and

Fig. 4

a perspective view of the inner bar and the bottom portion of the bag immediately before putting on the inner bar.

In Figure 1, the bottom area of a block bottom bag 10 is shown, for example consists of paper and inside with plastic (e.g. polyethylene) is coated. The bag has an upper wall 12 and a lower wall 14, which are connected to one another by gussets 16, and a base 18 with a rectangular plan, still in the state shown is not closed. The bottom 18 is made by four in one piece with the Main part of the bag formed bottom flaps, namely two of protruding trapezoidal tabs on the top and bottom walls of the bag 20 and two rectangular flaps lying in the extension of the side folds 16 22. The trapezoidal straps 20 and the rectangular straps 22 hang over Triangle turns 24 together, which are folded back onto the trapezoidal flaps 20 are.

In addition, the bottom has an inner bar 26 which is separated by a separate one Sheet is made of paper and also coated on the inside with polyethylene is. This inner bar 26 is on its longitudinal edges 28 with the Glued inner surfaces of the rectangular tabs 22 and the triangular folds 24 and is also on its narrow sides with the top in Figure 1 facing surfaces of the trapezoidal straps 20 glued.

To close the bottom 18, the trapezoidal tabs 20 are known Folded over inside and glued together.

Figure 2 shows the square blank in plan for the inner bar 26. The area of the blank which is visible in FIG. 2 is that which is laminated with polyethylene Inner surface, which points downwards in FIG. 1. The cut has side flaps 30, which are later folded back so that the corresponding fold lines form the longitudinal edges 28 of the inner bar. On the flaps 30 is a glue or hot melt adhesive in the form of adhesive lines 32 applied. With these adhesive lines 32 the folded over Flaps 30 of the inner bolt with the rectangular tabs 22 and the triangular folds 24 glued in Figure 1. Two further adhesive lines 34 run according to Figure 2 parallel to the other two edges of the blank. This Adhesive lines 34 are formed by contact adhesive and are used for gluing of the inner bolt with the trapezoidal flaps 20 and - in the area of the flaps 30 - with the triangular turns 24.

In Figure 3 is the bottom area of a blank for the actual bag 10 shown. Here, too, the visible side of the cut corresponds to the laminated one Inside of the bag. The cut is by longitudinal Fold lines 36 divided into several fields, according to the finished bag Figure 1 form the upper wall 12, the lower wall 14 and the side gussets 16. In addition, these fold lines 36 on the right edge of the blank in Figure 3, a fin 38 and an adhesive tab 40 formed with an adhesive line 42 made of glue or hot-melt adhesive is provided. The fin 38 and the adhesive tab 40 are on the associated fold lines 36, respectively folded over in opposite directions by 180 °, and the glue tab is then glued to the left edge of the wall 14 in Figure 3, so that the Cut to form a so-called fin seam to form a tube is closed. The use of a fin seam has the advantage that the Glue tab 40 with its side coated with polyethylene on the same coated side of the wall 14 comes to rest, so that the bag inside is completely lined with polyethylene and the paper through which Moisture could penetrate due to wicking, none Has connection to the inside of the bag.

The trapezoidal straps 20 and the rectangular straps 22 are formed by the main part of the bag separated by a transverse fold line 44. In parallel is another in the area of the upper wall 12 and the side gussets 16 transverse fold line 46 is provided which allows the bottom 18 in the manner shown in Figure 1 in the plane of the upper and lower walls 12, 14 to move. In the area of the lower wall 14, this fold line 46 is only shown in dashed lines because the material there in the state shown in Figure 1 is not folded. The longitudinal fold lines are corresponding 36 in the area of the rectangular tabs 22 only shown in broken lines. Here the material is only temporarily folded when the hose is made, and the folds will be undone later.

Diagonal folding lines 48 separate the triangular folds 24 from the trapezoidal flaps 20 and also form in the area of the side folds 16 further triangular folds that allow the gussets in the figure 1 shown to connect to the rectangular bottom 18.

The trapezoidal plate 20 lying in the extension of the upper wall 12 and the Adjacent triangular turns 24 are with a U-shaped adhesive line 50 provided, which is formed by contact adhesive and the counterpart to one the adhesive lines 34 of the inner bar 26 forms. In a similar way are the other trapezoidal tab 20 as well as the fin 38 and the adhesive tab 40 provided with L-shaped adhesive lines 52, 54 made of contact adhesive, which together form the counterpart to the other adhesive line 34 of the inner bar 26.

The bag 10 is placed in together with a plurality of similar bags a continuous process in the following manner.

The starting material that forms the blanks for the bags 10 is called Continuous web pulled off a roll. The outside made of paper the web can be printed with a label or other imprint his. Also the adhesive lines 50, 52 and consisting of contact adhesive 54 can already be printed on the web pulled off the roll, since the contact adhesive is only liable if it is also against a contact adhesive coated surface is pressed. Comes in the web wrap the contact adhesive but only with the non-adhesive paper side of the next web position in contact.

If the web is not yet printed with contact adhesive, the contact adhesive in the desired pattern on the one withdrawn from the roll Printed web or applied in any other way and the web runs through possibly a drying station.

The web then passes through a gluing station in which the adhesive line 42 is applied from hot melt adhesive.

The web is then folded along the fold lines 36 and into one Tube glued. The adhesive lines 50 and 52, 54 then come immediately However, lying on top of each other does not adhere to one another unless there is pressure it is exercised. Transport roller for the further transport of the hose attack near the longitudinal edges on the hose where the each other opposite sections of the adhesive lines 50 and 52, 54 by the intermediate Gussets 16 are separated. Hence effect these transport rollers also do not give premature adhesion to the contact adhesive.

The continuously transported hose is then in a punching or Cutting device cut into tube pieces to form the individual bags, and fold lines 44, 46, 48 are used as necessary pre-grooved by pre-grooving tools.

Then the hose pieces run on a floor laying drum, like them is usually used in the manufacture of floor bags.

The pieces of hose are successively on the peripheral surface of the floor laying drum stretched and run on the floor laying drum at a winding station past where the leading, bottom-side hose end is pulled up becomes. The rectangular tabs 22 and the trapezoidal tabs 20 then form together with the triangular turns 24 an approximately box-shaped Bottom opening, as shown in Figure 4.

At the same time, the roll material for the inner bars is made from another roll 26 peeled off, provided with the adhesive lines 34 made of contact adhesive and then dried if necessary and then cut to length. Subsequently the flaps 30 are folded over, and the folded over flaps are provided with the adhesive lines 32 made of glue or hot melt adhesive.

Meet at a placement station located on the circumference of the floor laying drum one bag and one inner bar together, and the inner bar 26 is inserted into the bottom opening of the bag as shown in Figure 4. The ends of the inner bar 26 are bent up to wings 56, so that they abut the inner surfaces of the trapezoidal plates 20. On in this way, the adhesive lines 34 of the inner bar come flush on the adhesive lines 50 and 52 of the bag to lie.

Then the bag with the inserted inner bar runs into a floor laying station, in which the trapezoidal straps 20 still erected in FIG. 4 are pulled apart be while the rectangular tabs 22 and the triangular turns 24 can be folded inside. In this way, the State shown in Figure 1.

By folding the triangular folds 24 at the fold lines 48 the legs running on these triangular angles together U-forming adhesive lines 52, 54 partly on the base leg of this U and partly on the adhesive lines 34 on the folded flaps 30 of the inner latch 26 to lie. The same applies to the legs of the U-shaped adhesive line 50, which is not recognizable in Figure 4. The rectangular tabs also lay down 22 on the flaps 30 of the inner bolt provided with hot-melt adhesive.

If in this state, for example with the help of a pressure roller Pressure on the bottom 18 of the bag spanned on the bottom laying drum is exercised, the desired adhesive connections between bags and inner bolt manufactured.

The trapezoidal flaps 20 are then flipped over in a closing station and glued. If necessary, the finished floor is then again with a Pressure roller rolled on. Optionally, rolling can only be done in this Stage take place, so that the rolling between the floor laying station and the closing station can be omitted.

In the example shown, the adhesive lines 32 of the inner bar become more normal Glue is used because these lines of glue are only on the top of the inner bar are in Fig. 3 so that the adhesive can be applied easily can be smeared without the bottom flaps. Optionally can However, 32 contact adhesives can also be used for these adhesive lines then interacts with corresponding adhesive lines on the rectangular tabs 22.

While in the embodiment shown here in Figure 3, the horizontal Legs of the adhesive lines 50, 52 are at the same height, it is provided according to the invention, these adhesive lines offset from one another to be arranged so that they do not lie on top of each other when cutting is closed into a hose. In this case it is possible the transport rollers for the transport of the hose or the hose pieces to be attacked also in the area between the side folds 16, or the procedure for a bag without side gussets, such as a cross bottom bag apply.

Claims (7)

1. Method for producing flat-bottom bags having an adhesively bonded inner tab (26), wherein a strip-shaped initial material for the bag (10) is closed to form a tube and is supplied to a base feeding station, characterised in that a contact adhesive is used for the inner tab and adheres only if two adhesive faces which are both coated with the contact adhesive are pressed against each other, in that the contact adhesive is applied to the initial material for the bag (10) before the initial material has been closed to form the tube, the adhesive faces (50, 52, 54) coated with contact adhesive being arranged offset relative to each other on the inner faces of the tube that are opposite each other, and in that the adhesive bonding is completed after the inner tab, which is provided at appropriate positions with contact adhesive, is positioned by application of pressure on the base (18) which is laid flat.
2. Method according to claim 1, characterised in that the initial material, which is closed to form a tube, passes over a base positioning drum to produce the base (18), and in that the inner tab (26) is positioned when the tube is located on the base positioning drum and the end of the base of the tube has been raised to form a base opening.
3. Method according to claim 2, characterised in that the application of pressure to the flattened base (18) having an inserted inner tab (26) is effected by rolling against the periphery of the base positioning drum.
4. Method according to any one of the preceding claims, characterised in that the inner tab (26) is provided, on the inner face facing the bag interior, with lines (34) of contact adhesive which extend parallel with two opposing edges of the inner tab, in that corresponding lines (50, 52) of contact adhesive are applied to the inner faces of two opposing base flaps (20), and in that the ends of the inner tab that are provided with the lines (34) of adhesive are folded over when the inner tab is inserted in the base opening of the bag to form wings (56) which abut the base flaps (20) so that the lines (34) of adhesive of the inner tab and the lines (50, 52) of adhesive of the base flaps (20) come into contact with each other.
5. Method according to claim 4, characterised in that the inner tab is provided, at the side directed outwards relative to the bag along the edges which extend at right-angles to the lines (34) of contact adhesive, with lines (32) of adhesive which are adhesively bonded to two other base flaps (22) of the bag.
6. Method according to claim 5, characterised in that the lines (32) of adhesive on the side of the inner tab (26), which is directed outwards relative to the bag, are applied to folded-over flaps (30) of a blank for the inner tab so that they are located at the same side of the blank as the lines (34) of contact adhesive.
7. Method according to claim 6, characterised in that the lines (50, 52, 54) of contact adhesive are applied to the base flaps (20) in such a manner that they extend beyond the inner tab and, with bent-over sides, extend over triangular folds (24) which are adjacent to the base flaps, and in that, when the triangular folds (24) are folded in, the sides of the lines of adhesive located there are brought into alignment with the respective portions of the lines of adhesive on the base flaps (20) and with corresponding portions of the lines (34) of adhesive on the folded-over flaps (30) of the inner tab.

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