Verfahren zum verschliessen eines sackkörpers

The invention concerns a procedure for locking a bag body from a fabric from monoaxially drawn polymere, in particular Polyolefinoder polypropylene small band, with which at least two Gewebelagen are connected by means of a seam extending over the width of the bag body, as well as a bag from a fabric from monoaxially drawn polymere, in particular Polyolefinoder polypropylene small band, more einoder reciprocally locked ist.

The invention concerns further a device for locking a bag body from a fabric from monoaxially drawn polymere, in particular Polyolefinoder polypropylene small band, in particular for the execution of the erfindungsgemäBen procedure, with a feeding device for supplying the bag body to a Verschließstation.

For the packing of goods, in particular bulk materials, different kinds are used by bags. The invention refers to bags, which consist Polyolefinoder polypropylene small band of a fabric of monoaxially drawn polymere, in particular. These small bands are usually manufactured Polyolefinoder polypropylene foils by aspect ratio of polymere, in particular on the 4 to 10 times, whereby the molecule chains are aligned in small band longitudinal direction and in this direction approx. the 6 to 10 times firmness opposite the original foil to exhibit. The small band width amounts to usually approx. 1.5-10 mm, the thickness 20-80 m.

A rough organization of such bags becomes by the distinction in Kissenund box form getroffen.

A cushion form of bags results usually from manufacturing the grounds with a textile seam or a welding seam. Kissenförmige of bags are supplied as ready-made, above open bags or however as tube material on a role• Partialfinished manufactured open above bags after filling are usually locked• ù “…: . [...] “.: ” '. “.

From tube material manufactured bags are manufactured directly on the racking plant, a so-called FFS plant (form, Fill and seal), by a seam at the ground and likewise locked above after filling by a seam. In case of a textile seam with needle the circumstance is unfavorable with the fact that it can come to a withdrawal of bag contents over the Nahtpeforierungen. In addition the seam perforation of the fabric causes weak points, so that the bag at the seam can break. In addition is the machine production of the textile seam connected with needle with a set of problems, as for example the danger of the Nadelbruchs and tearing the thread used for the seam. A further disadvantage is the feed speed of the sewing head limited when sewing, so that with at present available machines a processing of only approx. maximally 40 to 45 bags per minute is possible. Alternatively to the textile seam a welding seam can in similar way to the textile seam descriptive above at the ground and attached after filling above werden.

with foil bags In connection with a box form exhibiting bags are already different procedures for locking the grounds admit become. Usually folded ground after state of the art with Mehrkomponentenkleber complex stuck together, since Polypropylenund PL materials, of which the fabric consists usually, can be stuck together only under difficulties. Apart from the pedantic gluing procedure the well-known adhesives exhibit further disadvantages like small durability, brittleness due to temperature change and loss of the detention effect in moisture effects. In the WHERE 95/30598 A1 is in this connection an improved procedure described, with that at least a sagging, in particular a floor space, over an intermediate layer out, in particular thermoplastic, plastic, in particular polyolefin, preferably polypropylene material by thermal effect with a first page from fabric from monoaxially drawn polymere, in particular polyolefin, voroo! oo oo öooe ooe ö ““: :: [...] “oo • • oo oo ooo zugsweise polypropylene small bands, and with only the surface range outside present, in particular for less than 30% of the material thickness of the fabric small bands, is connected of floor space and first page due to the thermal effect disoriented molecules exhibits, whereby im übrigen materials area is present molecule orientation. Unfavorably with this procedure are control and delimitation of the thermal effect in such a manner that actually only the surface range outside present is affected accordingly heated up and by a disorientation of the molecules. Ranges of the fabric with disoriented molecules have a substantially smaller Festigkeit.

compared with ranges also by drawing the material oriented molecules - t the invention aims now off to arrange the bag catch in such a manner that the material of the bag is weakened by the catch if possible little, so that the locked bag does not tear also under high mechanical loads in particular within the range of the catch seam. In addition one is to be made possible for a conventional sewn catch seam clearly increased throughput rate in the comparison to the production. Further is the process security increased, which reduces maintenance of the machines, which production costs minimized and which are ensured optical Vorteilhaftigkeit of the product. The invention refers thereby particularly to bags with a Kissenform.

For the solution of this task the procedure of the kind initially specified is characterized according to invention by the fact that the seam is implemented as welding seam, whereby welding covers at least one ultrasonic welding step. The ultrasonic welding permits it here to receive in simple way defined welded joints so that the portion of the fabric within the range of the welding seam, concerned by welding, can be reduced. In particular if, how this corresponds to a preferential further training, the ultrasonic welding is made for the training of a multiplicity of in distance oo eeo oo ego welded joints from each other arranged, the fabric is weakened only in parts by the weld, whereby the firmness between the individual welded joints remains keeping complete. Since through the ultrasonic welding in only small extent the adjustment of the molecule chains is thus lost, the fabric hardly suffers firmness losses. Preferred with the fact it is proceeded in such a manner that the welded joints in several rows are arranged, whereby the welded joints of a row are arranged to the welded joints of a neighbouring row on gap. By the transferred arrangement of the welded joints the emergence of crack propagation lines becomes effective verhindert.

With the plastic ultrasonic welding by high frequency mechanical oscillations at the welded joints warmth is supplied to the small bands of the fabric which can be welded, whereby the material softens melted or at least wird.

The adding strength and the ultrasonic vibration exhibit the same effect direction. The introductory longitudinal waves cause a printing oscillatory stress in the material and in the adding zone, which leads to a plasticizing of the plastic. In the case of completion of the Energieeinschallung the material at the welded joints under pressure cools and it down develops a permanent, mechanically stable Verbindung.

The welding seam extends in accordance with the invention over the width of the bag body, so that due to the welding seam the side concerned of the bag is essentially perfectly locked. With bags with a valve, which results for example from hitting a Ecks to sagging inward, welding becomes likewise over those -- due to the hit Ecks according to reduced -- Width of the bag body made and extends accordingly also over the hit Gewebe.

With the procedure according to invention it is favourable that there are none by needle perforation of the fabric caused weak points. In addition the ultrasonic welding is connected with low costs and is characterised by a high operating speed. With the procedure according to invention more bags per minute than with from the conditions the technology admitted procedures can be locked clearly. The welded joint is not subjected to aging or embrittlement. There are beyond that simple disposal possibilities, there the bag exclusively from sort-pure material besteht.

However the danger exists with mentioned a welding seam manufactured by ultrasonic welding of the kind that peeling load an affecting the welding seam, with which the interconnected Gewebelagen in a direction are drawn apart transverse to the fabric surface to a loosening of the welded joint lead. It should be paid attention from there in principle to the fact that a such welded joint is only stressed on shearing, i.e. parallel to the fabric surface is only subjected to a load. For this purpose a preferential further training of the procedure according to invention plans that at least an open end exhibiting flat final section of the bag body is put down and that the ultrasonic welding step covers the ultrasonic welding of the put down final section with the bag body. By the rating of the final section the welding seam is exposed to no more peeling load, so that the seam can withstand also very high mechanical loads. This is in particular the case if, like this to a preferential further training corresponds, which put down final section welds turned Gewebelage of the bag body only connected with that the put down final section, in particular, wird.

Alternatively it can is also in such a way proceeded that the VerschweiBung of the two Gewebelagen of the final section takes place by means of ultrasonic welding in the not put down condition of the flat final section that after it the welded final section _-- • B, • • • oo ö • • • : • • o:

oo • • oo oo ooo • oo it is put down and that the put down final section is finally connected with the bag body. Connecting knows thereby for example by sticking, in particular extruding sticking or by hot-air welding erfolgen.

For avoidance one welding that the put down final section turned Gewebelage and that the put down final section turned away Gewebelage of the bag body is inserted with one another with advantage into the bag body an interface or an interface is applied. The interface exhibits prefers a higher heat conductivity than the bag fabric. The interface, in particular a metallhältige interface, is applied preferentially by a coating process. As interface here prefers a metallhältiger lacquer is used. A such interface leads due to the metal content to a heat dissipation, so that those is subject to the put down final section turned away Gewebelage of the bag body a smaller and/or essentially no heat entry. The heat entry been made by the oscillation body thereby, suggestable to ultrasonic vibrations, prefers on the put down Endabschnitt.

Peeling load welded joint anyhow always effectively prevented, if, how this corresponds to a preferential further training, on the basis of which due to the rating zuoberst to lie a number of directly lying on top of one another Gewebelagen is only interconnected to coming Gewebelage by ultrasonic welding, those around one increased half of the total number of the Gewebelagen entspricht.

In accordance with a further aspect of the invention a bag of the kind initially specified is intended, which it is in such a manner trained according to invention that at least a locked side exhibits a put down final section, only with that the put down final section turned the Gewebelage of the bag body connected, in particular ultrasonic-welded ist.

Preferential further educations are defined in the Unteransprüchen and essentially concern according to invention the Merkmale.

already mentioned in connection with the procedure In accordance with a further aspect of the invention a device is intended for locking a bag body from a fabric from monoaxially drawn polymere, in particular Polyolefinoder polypropylene small band in particular for the execution of the procedure according to invention, the one feeding device for supplying the bag body to a closing station umfasst.

The device is according to invention in such a manner trained further that the locking station a ultrasonic sealing station umfasst.

The invention becomes in the following on the basis a remark example represented schematically in the design more near erläutert.

In this Fig show. 1 a schematic cross section of a Schlauchgewebes for the production of a bag according to invention, Fig. 2 the fabric with put down final section, Fig. 3 the final section in welded condition, Fig. 4 an opinion in accordance with the arrow IV the Fig. 3 and Fig. 5 an increased opinion of the range V of the Fig. 4.

In Fig. 1 is represented a bag 1 from a Schlauchgewebe in flat condition, whose open end of 2 is to be locked for the production of a bag with cushion form. In the starting situation in accordance with Fig. two Gewebelagen 3 and 4 are evident to 1. If it concerns a bag with side folding, which is easily possible in the context of the available invention, four Gewebelagen are present in the range of the side folding. The invention becomes in the following however only on the basis a bag without side folding erläutert.

For locking the open end of 2 of the bag 1 now one proceeds as follows. First becomes, like this in Fig. dargeOQ is, the appropriate final section 5 places 2 on the bag body put down, so that in the range altogether four Gewebelagen come to be appropriate for the rating one on the other, i.e. the situations of 3, 4, 6 and 7. between the Gewebelagen 3 and 4 is arranged an interface 8. With the interface it can concern thereby a coating, which is applied at least either on that the Gewebelage 3 turned side of the Gewebelage 4 or on that the Gewebelage 4 turned side of the Gewebelage 3. The interface 8 prevents with the following ultrasonic welding that the Gewebelagen 3 and 4 are with one another permanently connected and the fabric layer damages 3 wird.

In Fig. schematically a ultrasonic sealing device is represented 2, comprehensive an anvil 9 and a Sonotrode I0.

For welding the Gewebelagen 3, 4, and the Sonotrode 10, are gotten jammed 6 and 7 between the anvil 9 as the anvil 9 and the Sonotrode i0 are too moved according to the arrows [...] on the section which can be welded. The Sonotrode is shifted in ultrasonic vibration, whereby at the contact points of the Sonotrode 10 at the fabric a welding is caused. The Gewebelagen 4, 6 and 7 are welded with one another. The interface 8 prevents a permanent connection of the Gewebelagen 3 and 4. if the Gewebelagen 3 and 4 after the welding procedure despite the interface 8 togetherful, then due to the interface no permanent connection between these Gewebelagen 3 and 4 is anyhow given 8, but these two Gewebelagen without can be further händisch separated without the material of the fabric to damage. The Gewebelagen become alternative if necessary when filling the bag due to the weight of the filling material from each other getrennt.

Fig. the sagging shows 3 in the locked condition. Because the Gewebelagen 3 and 4 are not connected, affects the weight of the filling material not in the sense of a peeling load the connections 4 to 6 and 6 to 7, but single - L oo o LDO 09 QOQ DOQ Q • • • • OqDLD • O0 OQQ 00 O0 OOQ • gg lich in the sense of a shear load. The connections can take up very high shear loads, so that the bag catch also with high loads receive bleibt.

Fig. the bag catch in an opinion in accordance with arrow IV the Fig shows 4. 3, whereby it is evident that the weld is trained in form over those entirely a width of the bag 1 extending welding seam. However the seam implemented with ultrasonic is designed not as continuous seam, but enclosure, as itself from the detail opinion in accordance with Fig. results in 5, shifts a multiplicity of arranged welded joints 13. The transferred arrangement of the welded joints 13 leads to the fact that the small bands concerned by welding are weakened not on their whole width by the structural change of the molecules caused by welding. Due to the raster-like arrangement of the welded joints 13 a stable connection of the Gewebelagen reached without the firmness of the fabric altogether crucially too beinträchtigen.

For the retention of a sufficient firmness it is sufficient, if the sum of the surfaces of the welded joints prefers 13 less than %, less as 25%, in particular less than % of the surface of the welding seam 12 beträgt.

The open end of 3 can be locked after filling the bag 1 in the same way as before in connection with locking the open end of 2 descriptive.