EP1601827A1

EP1601827A1 - Fabric consisting of plastic strips, and method and device for producing the same

Info

Publication number: EP1601827A1
Application number: EP04719329A
Authority: EP
Inventors: Peter Schmalholz
Original assignee: Starlinger and Co GmbH
Current assignee: Starlinger and Co GmbH
Priority date: 2003-03-11
Filing date: 2004-03-11
Publication date: 2005-12-07
Anticipated expiration: 2024-03-11
Also published as: BRPI0408227A; WO2004081273A1; AT413546B; JP2006519934A; ATE363561T1; US20050282696A1; DE502004003959D1; MXPA05009358A; EP1601827B1; CN1754017A; CA2511577A1; ATA3792003A; KR20060038915A

Abstract

The invention relates to a process and device for the manufacture of a cross ply of plastic tapes as well as to the cross ply itself. The process comprises: a) providing a transverse web ( 1 ) comprising transverse plastic tapes ( 1 a) interconnected by a synthetic layer ( 1 b), b) cutting transverse web pieces ( 1 c) of equal lengths from the transverse web ( 1 ) and conveying the transverse web pieces ( 1 c) to a connecting station ( 6 ), where the transverse web pieces ( 1 c) are drawn in transversely to the direction of the longitudinal axis of their transverse plastic tapes, c) providing a plurality of longitudinal plastic tapes ( 8 ), d) supplying the longitudinal plastic tapes ( 8 ) in parallel arrangement to the connecting station ( 6 ), e) connecting the longitudinal tapes ( 8 ) with supplied transverse web pieces ( 1 c) at the connecting station ( 6 ) to form a cross ply ( 11, 19 ) by introducing a plastic melt layer ( 10 ) between the longitudinal plastic tapes ( 8 ) and the transverse web pieces ( 1 c) as they are passed through the connecting station ( 6 ), and subsequent cooling of the plastic melt layer so that the direction of the longitudinal axis of the longitudinal plastic tapes ( 8 ) runs at an angle relative to the direction of the longitudinal axis of the plastic tapes of the transverse web pieces ( 1 c).

Description

Nonwoven fabric made of plastic tapes and method and device for its production

The invention relates to a method and a device for producing a scrim from, preferably stretched, plastic tapes, and to a scrim made of plastic tapes.

Nowadays, fabrics made of stretched plastic tapes are widespread and are mainly used in sack production, tarpaulin fabrics, "big bags" with a load capacity of 1000 kg and more, geotextile, etc. Compared to other fabrics such as foils, fabrics are characterized by higher biaxial strength with less Basis weight. Furthermore, the production process of plastic tapes is technologically relatively simple compared to the production of foils. However, the production process of woven fabrics from plastic tapes is associated with considerable disadvantages, such as high space and personnel requirements, noise, dirt, high waste content, loss of strength of the tapes during weaving, etc.

From WO 01/16418 a method and a device for producing composite panels is known, a bundle of parallel yarns being guided along a predetermined direction. A yarn layer which is oriented transversely to the above direction is connected to these yarns, the yarn layer and / or the yarn bundle containing at least one organic material and at least one reinforcing material. The overall arrangement contains at least 10% by weight of organic material. The overall arrangement is heated while being moved in the predetermined direction, and is fixed by the heating and / or pressure and then cooled, so that a composite web is formed. A disadvantage of this known device and the method, however, is that in the embodiment according to FIG. 1 of this document, the production process can only take place very slowly, since a single yarn is beaten across the bundle of yarn (specified speed: 120 beats / minute) and then cut off must become. In the embodiment according to FIG. 2, in which several yarns are guided across the yarn bundle at the same time, either no continuous movement of the yarn bundle is possible, or - contrary to the illustration - no perpendicular arrangement of the transverse yarns over the yarn bundle is possible, since in addition to the transverse speed - Component of the transverse yarns would always have a longitudinal velocity component of the yarn bundle.

From DE 27 07 584 AI, a layer-reinforced sheet of film is known, the layer of zigzag-shaped ribbons extending and crossing each other consists. The manufacturing process comprises moving the film web under a rake or comb which is movable transversely to the conveying direction of the film web and which applies a coulter of ribbons in parallel to the film web, the ribbons being fixed to the film web by simultaneous application of glue. Due to the relative movements of the film web and rake, the ribbons lie on the film web at an oblique angle. In addition, thickening points arise on the longitudinal edges of the film web, which are caused by the reversal of the direction of the position of the ribbon coulter.

The present invention has for its object to provide a method and an apparatus for producing a scrim from, preferably stretched, plastic tapes, and a scrim made of plastic tapes, in which the disadvantages mentioned above are avoided.

To achieve the object specified above, the invention provides a method for producing a scrim from plastic tapes as defined in claim 1. Advantageous refinements of the method according to the invention are set out in the dependent subclaims.

The method according to the invention offers the following advantages:

o high throughput in manufacturing

• low space and personnel requirements • high overall efficiency

• no loss of strength due to the process

According to an advantageous embodiment of the method according to the invention, the cross web is provided by first providing a plurality of cross plastic tapes, preferably in spools on unwinding gates, which are then guided in parallel to a coating station, where respective adjacent cross plastic tapes pass through Applying a plastic layer to at least one surface of the transverse plastic tapes are connected to one another. This process can be carried out synchronously with the feeding of the longitudinal plastic tapes to the connecting station, so that the entire fabric can be made from plastic tapes in one integrated operation. In order to impart desired properties to the scrim or to support its further processing, a further development of the method for scrim production involves coating the longitudinal plastic tapes with a plastic layer on at least one of their surfaces in a coating station before they are fed into the connecting station. This results in a 5-layer scrim with the desired properties.

A favorable further development of the method for fabric production according to the invention, in which both the longitudinal plastic tapes and the transverse plastic tapes are coated in a single common coating station before being fed to the connecting station, is set out in claim 3. A 5-layer fabric can thus be produced using a single coating station and the connecting station.

A fabric with reinforced side edges, which are also protected against fanning out, can be achieved if one end of the transverse plastic ribbons protruding laterally beyond the longitudinal plastic ribbons and the folded end of the transverse plastic ribbons with itself or the longitudinal plastic ribbons, preferably by hot air or extrusion welding.

The scrim obtained by the method according to the invention was preferably further treated by printing on the outer scrim surface or by shaping the scrim into a tube, possibly with subsequent cutting and bag bottom formation.

To achieve the above-mentioned object, the invention also provides a device for producing a scrim from plastic tapes as defined in claim 7.

The device according to the invention is characterized by high performance, small space requirements, low operating personnel requirements, low maintenance requirements and minimal environmental impact.

The pressing means advantageously comprise a pair of press rolls, preferably at least one of the press rolls being cooled.

In a preferred embodiment, the molten plastic nozzle is designed as a slot die. The transport means for the transverse web pieces advantageously comprise a conveyor belt, preferably a vacuum conveyor belt. This enables high transport speeds to be achieved, while at the same time the transverse web sections are held in a defined position on the belt.

For an integrated sequence of the work steps to be carried out by the device, the cutting means can be equipped with transfer means, e.g. reciprocating suction beams can be combined to transfer cut cross web pieces directly to the means of transport. The space requirement of the device is further reduced by this measure.

Smooth cuts in the cross web are ensured if the cutting means are designed as a movable knife or as a hot wire.

The device according to the invention for producing a scrim of plastic tapes can further be provided with one or more coating stations in order to coat the transverse plastic tapes and / or the longitudinal plastic tapes with a plastic layer on at least one of their surfaces before they are fed into the connecting station. As a result, the properties of the fabric created can be largely varied. Likewise, the cross web can be produced in one production process and the longitudinal plastic tapes (coated or uncoated) can be fed to the connecting station synchronously, so that a highly integrated device is created. The transverse plastic tape coating station and / or the longitudinal plastic tape coating station preferably comprise at least one nozzle for dispensing plastic melt and downstream press and coolant, preferably a pair of press and chill rolls.

A particularly preferred embodiment of the device according to the invention for producing a scrim made of plastic tapes, which offers the highest throughput with uniformly good quality, comprises a plastic tape coating station for producing a plastic web by coating a plurality of plastic tapes fed in parallel with one another, and a separating device downstream for longitudinal separation the plastic web into a cross web and a longitudinal web, deflection means for supplying the cross web to the cutting means are provided and the longitudinal web can be fed to the connecting station. With this embodiment, 5-layer fabrics can be produced, only one coating station and one connecting station being required. To achieve the above-mentioned object, the invention provides a scrim made of plastic tapes as defined in claims 17 and 18.

The scrim of the invention can be 4-ply or 5-ply. It obtains its biaxial mechanical strength from the layers of transverse plastic ribbons and longitudinal plastic ribbons arranged at an angle to one another, which are advantageously uniaxially stretched to increase the strength. The two layers of transverse plastic ribbons and longitudinal plastic ribbons are connected to one another by the inner plastic layer, the inner plastic layer itself not being exposed to any significant mechanical stress, but primarily serving to splice the layers of transverse plastic ribbons and longitudinal plastic ribbons to prevent. The one or two outer plastic layers serve on the one hand to protect the layers of transverse plastic tapes and longitudinal plastic tapes arranged underneath, but on the other hand also to provide the fabric with desired properties, e.g. Giving slip resistance, UV resistance, air or dust impermeability, good printability etc. Cross plastic tapes and longitudinal plastic tapes can consist of different materials and / or specifications. Perforation can also be used to create air-permeable fabrics.

The main advantages of the scrim according to the invention are a very high mechanical strength, based on the weight per unit area, the extensive variability of its properties, the universal applicability, the high resistance to displacement of individual plastic tapes and the excellent further processing in subsequent processes, e.g. in the production of sacks, etc.

In a preferred embodiment of the fabric offering great advantages for the fabrication of the fabric, the transverse plastic tape layer consists of individual transverse web pieces arranged one after the other edge by edge made of plastic tape connected to one another by the plastic outer layer.

In a further development of the fabric, an edge of the transverse plastic ribbons that projects laterally beyond the longitudinal plastic ribbons is folded over and connected to itself or the longitudinal plastic ribbons, so that an effective edge reinforcement is achieved.

The plastic material for the plastic tapes and the individual plastic layers made of polypropylene (PP), polyethylene (PE), in particular HDPE, LDPE, is preferred or LLDPE, or, their mixtures selected. To achieve desired properties, such as UV resistance, slip resistance, good weldability, antistatic properties, additives such as color batch, calcium carbonate, fillers, UV protection agents, etc. can be added to the plastic material. To achieve high strength of the scrim, the carrier material for the plastic tapes should be selected from film tapes, preferably mono- or coextruded film tapes, monoextruded tapes, monofilaments such as monofilaments made of PET or PA, and multifilament yarns. The tapes are preferably subjected to a stretching process. The outer lamination of the scrim and the middle connecting plastic layer can have different thickness and composition (e.g. a middle layer with a high homopolymer content, an outer layer with a high copolymer content, to improve weldability, etc.) Furthermore, it is possible to use mechanical methods (e.g. Needling) to set a defined gas or liquid permeability of the scrim.

The invention will now be explained in more detail by means of non-limiting exemplary embodiments with reference to the drawings.

1 and 2 show a first embodiment of a device according to the invention and the method running thereon for producing a scrim from plastic tapes, schematically in perspective and in side view; 3 and FIG. 4 schematically show a second embodiment of a device according to the invention for producing a scrim from plastic tapes in perspective and in side view; 5, 6 and 7 show a third embodiment of a device according to the invention for producing a scrim from plastic tapes schematically in perspective and in side view, or FIG. 7 shows a detail of this embodiment in perspective; 8, 9 and 10 show a fourth embodiment of a device according to the invention for producing a scrim from plastic tapes schematically in perspective or in side view, or FIG. 10 shows a detail of this embodiment in perspective; 11 and FIG. 12 schematically show a fifth embodiment of a device according to the invention for producing a scrim from plastic tapes in perspective and in side view; 13 shows a five-layer fabric made of plastic tapes in perspective, produced in a device according to the second, fourth or fifth embodiment; FIG. 14 shows a detail of the scrim of FIG. 13 in perspective; 15 is a perspective view of a 5-layer fabric made of plastic tapes, produced in a device according to the second, fourth or fifth embodiment; FIG. 16 shows the scrim of FIG. 15 formed into a tube Cross section and in an enlarged detail; 17 is a perspective view of a 4-ply fabric made of plastic tapes, produced in a device according to the first or third embodiment; and FIG. 18 shows the scrim of FIG. 17 formed into a tube in cross section and in an enlarged detail.

1 and 2 schematically show a first embodiment of a device according to the invention and the method running thereon for producing a scrim from plastic tapes in perspective or in side view.

In a storage, not shown, a transverse web 1 wound into a bale is provided. This cross web 1 consists of a plurality of parallel plastic tapes la arranged in parallel, each of which is connected to adjacent cross plastic tapes la by means of a plastic layer 1b. The transverse plastic tapes are preferably uniaxially stretched plastic tapes made of polypropylene (PP) or polyethylene (PE), in particular HDPE, LDPE or LLDPE, or mixtures thereof. The plastic layer 1b, preferably a polyolefin layer, only has to have such a strength that the transverse plastic tapes 1 a do not slip, are separated from one another or split apart during processing. However, the plastic layer 1b does not have to withstand any wear. The transverse web 1 is guided via various deflection rollers 14a, 14b, 14c, 14d to an integrated cutting and transfer station 2, which comprises two suction bars 3 arranged transversely to the feed direction (arrow A), which are moved back and forth by means of a slide 4 Are movable, as well as cutting means, not shown, which can comprise a hot wire or a fixed or movable knife. The carriage 4 pulls the transverse web 1 adhering to the suction bar 3 via transport means in the form of a conveyor belt 5, which is preferably designed as a vacuum conveyor belt. As soon as the transverse web is in the predetermined position above the conveyor belt 5, a transverse web section 1c of a defined length is cut off and transferred to the conveyor belt 5. As an alternative to this, the transverse web section 1c can also be cut off before the carriage 4 moves over the conveyor belt 5, so that the carriage only transports the transverse web section.

The conveyor belt 5 moves continuously in the direction of arrow B, and the feed stroke of the cross web pieces 1c on the conveyor belt 5 is set such that the cross web pieces come to lie on the conveyor belt edge to edge in a successive relationship, whereby the The longitudinal axes of the transverse plastic tapes extend at right angles to the conveying direction of the conveyor belt 5. The successive transverse web pieces lc are fed to a connecting station 6 and thus into the Connection station 6 pulled in that the longitudinal axes of the transverse plastic tapes are transverse to the feed direction.

It should be pointed out that the illustrated embodiments of the cutting, transfer and transport means are currently preferred exemplary embodiments. However, the scope of the invention is in no way limited to these examples, but results solely from the appended claims.

Simultaneously with the process of feeding the cross web, cutting off cross web pieces and feeding them to the connection station, the corresponding plurality of, preferably uniaxially stretched, longitudinal Plastic tapes 8 unwound and lying parallel to each other (either edge to edge, or with a small distance between the tapes) via various UmlenkiOllen 13a, 13b, 13c to the connection station 6 (see arrow C). The longitudinal plastic tapes are drawn in so that their longitudinal axes lie in the feed direction.

The transverse web pieces 1c and the longitudinal plastic strips 8 are drawn in between a pair of rollers, one roller 5a of which is part of the conveyor belt 5 and the other roller 9 is a cooled press roller. The connecting station 6 comprises a nozzle 6a, preferably a slot die, from which a plastic melt layer 10 is introduced between the transverse web pieces 1c and the longitudinal plastic tapes 8 when they are drawn into the pair of rollers 5a, 9. The melted plastic layer 10 is cooled and fixed by the cooled press roller 9. The plastic melt layer 10 connects the transverse web pieces 1c and the longitudinal plastic tapes 8 to one another to form a scrim 11, which has high biaxial strength due to the two layers of uniaxially stretched transverse plastic tapes and longitudinal plastic tapes, which are approximately at right angles to one another. The fabric 11 thus produced consists of four layers, namely the plastic layer 1b, the transverse plastic tapes 1 a, the plastic melt layer 10 and the longitudinal plastic tapes 8, as shown in FIG. 17. The scrim 11 can then be processed further, for example by folding and heat welding the longitudinal edges in the folding and gluing station 30, printing, etc. Then the scrim 11 is rolled up into a bale 12.

Further exemplary embodiments are explained below, elements in the drawings which are the same or have the same function being provided with the same reference symbols as in the first embodiment. FIGS. 3 and 4 schematically show a second embodiment of the device according to the invention and of the method running thereon for producing a scrim from plastic tapes in perspective or in side view.

As in the first embodiment, there is provided a cross web 1 wound into a bale, which was generated in an earlier manufacturing process. This transverse web 1 consists of a plurality of parallel transverse plastic tapes 1 a, which are each connected to adjacent transverse plastic tapes 1 a by means of a plastic layer 1 b. The cross web 1 is led via various UmlenkiOllen to the integrated cutting and transfer station 2, where it is pulled over the conveyor belt 5 and cut into cross web pieces lc of the same, predefined length, which in a successive relationship edge to edge on the continuously Moving conveyor belt 5 are transferred, the longitudinal axes of the transverse plastic tapes extending at right angles to the conveying direction of the conveyor belt 5. The successive transverse web pieces 1c are fed on the conveyor belt 5 to the connecting station 6 and drawn into the connecting station in such a way that the longitudinal axes of the transverse plastic tapes lie transversely to the feed direction.

Simultaneously with the process of feeding the cross web, cutting off cross web pieces and feeding them to the connecting station, uniaxially stretched longitudinal plastic tapes 8 are unwound from a plurality of spools 7 and guided parallel to one another via various deflecting rollers to the connecting station 6. The longitudinal plastic tapes are drawn in so that their longitudinal axes lie in the feed direction. In contrast to the first embodiment, the longitudinal plastic tapes 8 are, however, passed through a coating station 15 before being drawn into the connecting station 6, where they are coated with a plastic layer 16 which binds the individual tapes 8 to one another. The coating station 15 comprises at least one nozzle 15a, preferably a slot die, from which the plastic layer 16 is applied as a melt to the tapes 8. The tapes pass through a pair of press rolls 17, 18 with the plastic layer already applied, of which at least one roll is cooled.

The further process of producing the scrim corresponds to that of the first embodiment, that is to say the transverse web pieces 1c and the longitudinal plastic tapes 8 with their coating 16 are drawn in between the pair of rollers 5a, 9, it being noted that the plastic layer 16 and the Plastic layer lb are on the outside, ie they rest on the roller surfaces, and therefore not with the Plastic melt layer 10 come into contact, which is introduced from the connecting station 6 between the transverse web pieces 1c and the longitudinal plastic tapes 8. The melted plastic layer 10 is cooled and fixed by the cooled press roller 9. The plastic melt layer 10 connects the transverse web pieces 1c and the longitudinal plastic tapes 8 to one another to form a scrim 19 which, owing to the two layers of uniaxially stretched transverse plastic tapes and longitudinal plastic tapes, which are approximately at right angles to one another, has high biaxial strength. The fabric 19 thus produced consists of five layers, namely the plastic layer 1b, the transverse plastic tapes 1 a, the plastic melt layer 10, the longitudinal plastic tapes 8 and the plastic layer 16, as shown in FIGS. 13-16. The scrim 19 is then rolled up into a bale 20.

FIGS. 5 and 7 show a third embodiment of the device according to the invention for producing a scrim from plastic tapes, which is to be regarded as a variant of the first embodiment. This embodiment differs from the first two embodiments in that the transverse web is not already provided prefabricated, but is generated in-line during the fabrication process of the scrim. For this purpose, plastic crossbands la are unwound from a sub-group 7b of the coils 7 and fed in a parallel arrangement to a coating station 21, where they are coated with a plastic layer 1b from a nozzle 21a. Following the coating process with the plastic layer 1b, the transverse bands pass through a pair of press rollers 22, 23, of which at least one roller is cooled in order to fix the plastic layer 1b. The cross web 1 thus produced is deflected by 90 ° on a turning bar 24 and then fed under the conveyor belt 5 to the cutting and transfer station 2, where it is cut into cross web pieces 1 c, which are transferred to the conveyor belt 5 and to Connection station 6 are transported. In a manner known from the first embodiment, longitudinal tapes 8 are unwound from a sub-group 7a of the coils 7 and are led to the connection station 6, where, as in the first embodiment, they form a 4-ply with the transverse web pieces 1c by introducing a plastic melt layer 10 in between Scrim 11 (shown in Fig. 17) are connected, which is rolled up into a bale 12. 7 shows a detail of the third embodiment, which includes the cutting and transfer station, in perspective. The suction bars 3 have been brought into a position above the conveyor belt 5 by the carriage 4. By means of a knife 28 attached to the rear edge of one of the suction bars 3, a transverse web piece 1c was cut from the transverse web 1 and is held by the suction bars 3. Thereupon the over the Conveyor belt arranged part of the carriage 4 tilted down by the angle α, so as to transfer the cross web piece lc to the conveyor belt 5.

8, 9 and 10 show a fourth embodiment of the device according to the invention for producing a scrim from plastic tapes. In this case, longitudinal plastic tapes 8 are withdrawn from a first sub-group 7a of coils 7 and, synchronously therewith, transverse plastic tapes 1 a are withdrawn from coils 7b of coils 7. The longitudinal plastic tapes 8 and the transverse plastic tapes 1 a are fed together in a parallel orientation to a coating station 25, where they are (also together) coated with a plastic layer 27. The tapes with their coating are then pulled through a pair of press rollers 28, 29, of which at least one roller is cooled. The web thus produced then arrives at a fixed knife 26, on which it is separated lengthwise into two partial webs, namely into a longitudinal web 8a, consisting of the longitudinal plastic tapes 8 and the coating 27 (which have the same function as the plastic layer 16 of the second Embodiment is), and a transverse web 1, consisting of the transverse plastic tape la and the coating 27 (which is functionally identical to the plastic layer lb of the first to third embodiments). The further processing takes place as in the second embodiment, i.e. on the one hand, the coated longitudinal web 8a is fed to the coating station 6, and on the other hand, the transverse web 1 is turned on the turning bar 24, fed under the conveyor belt 5 to the cutting and transfer station 2, where it is cut into transverse web pieces 1c, which transferred to the conveyor belt 5 and fed to the coating station 6 one behind the other. In the coating station 6, the longitudinal plastic tapes 8 and the transverse web pieces 1c are connected by inserting a plastic melt layer 10 in between to form a 5-layer fabric 19, which is shown in detail in FIGS. 13-16. FIG. 10 shows a detail of the fourth embodiment, which includes the cutting and transfer station, in perspective. The suction bars 3 have been brought into a position above the conveyor belt 5 by the carriage 4. By means of a knife 28 attached to the rear edge of one of the suction bars 3, a transverse web piece 1c was cut from the transverse web 1 and is held by the suction bars 3. Thereupon, the part of the slide arranged above the conveyor belt is tilted downward by the angle α in order to transfer the transverse web piece 1c to the conveyor belt 5.

FIGS. 11 and 12 show a fifth embodiment of the device according to the invention for producing a scrim from plastic tapes. This differs from the previous embodiments in that both for Coating of the longitudinal ribbons 8 and also for coating the transverse ribbons a separate coating station is provided, namely the coating station 31 for applying a plastic layer 16 to the longitudinal ribbons 8, and the coating station 32 for applying a plastic layer 1b to the transverse ribbons la. The further manufacturing process of the scrim takes place as described above with reference to the second embodiment, which is why it is sufficient to refer to this description. With this device, a 5-layer fabric 19 is produced, as shown in FIGS. 13-16.

FIG. 13 shows the scrim 19 produced by the second, fourth or fifth embodiment of the device according to the invention in perspective. It comprises five layers, namely a plastic outer layer formed by the plastic layer 1b of transverse web pieces 1c, a layer of transverse plastic tapes 1b of the transverse web pieces 1c, a plastic inner layer formed by the melted plastic layer 10 inserted in the connecting station Layer of longitudinal plastic tapes 8, and a plastic layer 16 or 27, with which the longitudinal plastic tapes 8 were coated. The longitudinal plastic tapes 8 extend in the longitudinal direction of the scrim 19; across it, i.e. at right angles, the transverse plastic tapes la. The plastic inner layer 10 binds the transverse plastic tapes 1 a and the longitudinal plastic tapes 8 to one another, but it does not have to have any wear resistance itself. The load-bearing strength of the scrim is based almost exclusively on the strength of the stretched longitudinal and transverse plastic tapes, which, through their arrangement at right angles, give the scrim the desired biaxial strength. By stretching, the plastic tapes have aligned molecules, which increases the strength many times over. The plastic melt layer 10 connecting the ribbon layers and the plastic outer layer 1b have unoriented molecular chains. The plastic outer layer 1b serves to impart certain desired properties to the scrim, e.g. UV resistance, anti-slip ability, good printability etc.

Polyolefins, such as polypropylene (PP), polyethylene (PE), in particular HDPE, LDPE or LLDPE, or mixtures thereof, are suitable as the material for the plastic tapes and the individual plastic layers. In addition, additives such as color batch, calcium carbonate, filler materials, UV protection agents etc. can be added. An example of the scrim according to the invention includes highly stretched PP (homopolymer) with admixtures (additives), possibly with a mixture proportion of LDPE, with a coating of a mixture of PP with LDPE (homo- or copolymers) plus possibly additives to increase weldability or adhesion and additives for coloring or adjusting various properties (UV protection, antistatic, conductivity etc.)

Depending on the application, either film tapes, mono-extruded tapes, other monofilaments and multifilament yarns are suitable as carrier material. The use of mono or co-extruded film tapes or monofilaments made of PET or polyamide (to increase strength) is also conceivable. Coextruded multilayer film tapes made of polyolefins are also possible. The area coverage of the tapes or mono / multifile in the scrim can vary between approximately 100% and a net-like structure. Furthermore, the use of different backing materials (e.g. thin polyolefin tapes for filling, with PET threads in between for strength) is possible in a scrim. The outer lining of the scrim and the middle adhesive layer (connecting plastic layer 10) can have different thickness and composition (e.g. a middle layer with a high homopolymer content, an outer layer with a high copolymer content, to improve weldability, etc.) All variants are based on the intended use , It is also possible to use mechanical methods (e.g. needling) to set a defined gas or liquid permeability. The further processing into hoses for sacks is generally carried out using hose forming systems with longitudinal and transverse gluing or welding.

The thicknesses of the individual layers of material are selected depending on the intended use of the scrim. The scrim according to the invention is used, for example, in sack production, in tarpaulin fabrics, “big bags”, geotextiles, etc. The basis weight of the scrim can be from about 70-80 g / m ² for normal sacks and tarpaulins up to a multiple thereof for container, technical and special applications are sufficient. If desired, the scrim can be perforated to achieve air permeability. It is also not necessary that the ribbons of the respective layer lie edge to edge, but they can also be arranged at a distance from one another.

FIG. 14 shows an enlarged edge section of the scrim 19 of FIG. 13. It can be seen that an edge of the transverse plastic tapes 1 a laterally beyond the longitudinal plastic tapes 8, together with the plastic layer 1 b connecting them, is folded over and with the plastic layer 16 or 27 is connected. This creates a reinforced edge 19a of the scrim, which prevents splitting. Of course, the formation of a reinforced edge can also take place with 4-ply fabrics. In this case the plastic tapes la would be connected to the longitudinal plastic tapes 8.

15 shows the perspective view of the 5-layer fabric 19 produced by the second, fourth or fifth embodiment of the device according to the invention for producing a fabric, formed into a tube. Fig. 16 shows the molded tube in cross section. The scrim of Figures 15 and 16 comprises, as mentioned, five layers, namely a plastic outer layer formed by the plastic layer 1b of the transverse web 1, a layer of transverse plastic tapes la of the transverse web 1, a plastic inner layer from the plastic melt layer 10 introduced in the connecting station, a layer of longitudinal plastic tapes 8, and a plastic layer 16 or 27, with which the longitudinal plastic tapes 8 were coated. The plastic layer 16 or 27 forms an inner layer during the tube formation of the scrim, which, for example in bag production, has significant advantages over a manufacturing method with round woven tubes, since the inner layer does not have to be created subsequently.

According to the invention, several layers of transverse and longitudinal plastic tapes can also be formed into a fabric in order to achieve even higher load-bearing capacities. For example, two or more 4- and 5-layer fabrics could be connected to one another by inserting a plastic melt layer between two fabrics. In the first or third embodiment of the device according to the invention, a scrim produced in a previous work step could possibly also be used as the transverse web.

17 shows the scrim 11 produced by the first or third embodiment of the device according to the invention in perspective. It comprises four layers, namely a plastic outer layer formed by the plastic layer 1b of cross web pieces 1c of cross web 1, a layer of cross plastic tapes 1a of cross web pieces 1c of cross web 1 (see FIGS. 1 and 3) , a plastic inner layer, formed from the melted plastic layer 10 introduced in the connecting station, and a layer of longitudinal plastic tapes 8. The longitudinal plastic tapes 8 extend in the longitudinal direction of the scrim 11; transverse to it, ie at right angles, the transverse plastic tapes la. The plastic inner layer 10 binds the transverse plastic tapes 1 a and the longitudinal plastic tapes 8 to one another, but it does not have to have any wear resistance itself. The load-bearing capacity of the scrim is based almost exclusively on the strength of the stretched longitudinal and transverse plastic ribbons, due to their arrangement in the right Winlcel give the scrim the desired biaxial strength. By stretching, the plastic tapes have aligned molecules, which increases the strength many times over. The plastic melt layer 10 connecting the ribbon layers and the plastic outer layer 1b have unoriented molecular chains. With regard to the materials and properties of the scrim, reference is made to the above 5-layer embodiment, the description of which also applies to the 4-layer embodiment.

Claims

claims:

1. A process for producing a scrim from, preferably stretched, plastic tapes, characterized by:

a) the provision of a cross web (1) with a plurality of parallel plastic tapes (la) arranged in parallel, each of which is connected to adjacent cross plastic tapes (la) by means of a plastic layer (lb),

b) the cutting of cross web pieces (lc) of equal length from the cross web (1) and transporting the cross web pieces (lc) in successive relationship to a connecting station (6) where the cross web pieces (lc) so are pulled in that the longitudinal axis direction of the transverse plastic tapes is at an angle, preferably approximately at a right angle, to the feed direction (arrow B),

c) the provision of a plurality of longitudinal plastic tapes (8), preferably in coils (7) on unwinding gates,

d) feeding the longitudinal plastic tapes (8) in a parallel arrangement to the connecting station (6),

e) the connection of the longitudinal tapes (8) with respectively supplied transverse web pieces (lc) at the connecting station (6) to a fabric (11, 19), by introducing a plastic melt layer (10) between the longitudinal plastic tapes (8) and the crossbeam pieces (lc) during their passage through the connecting station (6), and then cooling the plastic melt layer so that the longitudinal axis direction of the longitudinal plastic tapes (8) is at an angle, preferably approximately at right angles, to the longitudinal axis direction of the plastic tapes Cross-track sections (lc) runs,

f) further processing and / or rolling up the scrim thus produced (11, 19).

2. The method according to claim 1, characterized in that the provision of the transverse web, the provision of a plurality of transverse plastic tapes (la), preferably in spools (7) on unwinding, the supply of the transverse plastic tapes (la) in a parallel arrangement to a coating station (21, 32), and the connection of respective adjacent transverse plastic tapes (la) in the coating station (21, 32) Applying a plastic layer (lb) on at least one surface of the transverse plastic tape (la) comprises.

3. The method according to claim 1 or 2, characterized in that the longitudinal plastic tapes (8) before being fed into the connecting station (6) in one

Coating station (15, 31) are coated with at least one of their surfaces with a plastic layer (16).

4. The method according to claim 3, characterized in that the provision of the transverse web (1) and the coating of the longitudinal plastic tape (8) the provision of a

A large number of plastic tapes (la, 8), preferably in spools (7) on an unwinder, feeding the plastic tapes (la, 8) in parallel to a coating station (25), connecting the plastic tapes (la, 8) in the coating station ( 25) to a web by applying a plastic layer (27) to at least one surface of the plastic tapes (la, 8), the lengthwise separation of the web thus obtained into a longitudinal web (8a) which is fed to the connecting station (6), and a transverse path (1) which is turned by a predetermined angle, preferably a right angle, and cut into transverse path pieces (lc) of the same length, the transverse path pieces (lc) being in successive relationship to the connecting station (6) be transported.

5. The method according to any one of claims 1 to 4, characterized in that the further treatment of the scrim (11, 19) turning over one side of the transverse plastic ribbon (la) projecting laterally beyond the longitudinal plastic ribbon and connecting the folded end of the cross - Plastic tapes with themselves or the longitudinal plastic tapes (8), preferably by hot air or extrusion welding.

6. The method according to any one of claims 1 to 5, characterized in that the further treatment of the scrim (11, 19), the printing on the outer surface of the scrim, or the

Forming the scrim into a tube, possibly with subsequent cutting and bag bottom formation.

7. Device for producing a scrim from, preferably stretched, plastic tapes, characterized by: a) cutting means (28) for cutting cross web pieces (lc) from a cross web (1) with a plurality of parallel plastic tapes (la) arranged in parallel, each with adjacent cross plastic tapes (la) by means of a plastic layer (lb ) are connected,

b) Transport means (5) to feed the transverse web pieces (lc) one behind the other to a connection station (6) in such a way that the longitudinal axis direction of the transverse plastic tapes is essentially transverse to the direction of transport (arrow B) of the transverse web pieces (lc) .

c) the connecting station (6) for connecting the transverse web pieces (lc) with a plurality of longitudinal plastic tapes (8), the connecting station (6) at least one plastic melt nozzle (6a) for introducing a plastic melt layer (10) between the Longitudinal plastic tapes (8) and the transverse web pieces (lc) during their passage through the connecting station (6), pressing means (5a, 9) around the longitudinal plastic tapes (8) and the transverse web pieces (lc) with the in between lying plastic melt layer (10) against each other, and comprises coolant (9) in order to cool and solidify the plastic melt layer (10).

8. Device for producing a scrim according to claim 7, characterized in that the pressing means comprise a pair of press rollers (5a, 9), preferably at least one of the press rollers (9) being cooled.

9. The device for producing a scrim according to spoke 7 or 8, characterized in that the molten plastic nozzle (6a) is designed as a slot die.

10. The device for producing a scrim according to one of claims 7 to 9, characterized in that the transport means for the transverse web pieces (lc) comprise a conveyor belt (5), preferably a vacuum conveyor belt.

11. The device for producing a scrim according to one of claims 7 to 10, characterized in that the cutting means (28) with transfer means, for example reciprocating suction bars (3), are integrated to cut transverse web pieces (lc) on the Transfer means of transport (5).

12. Device for producing a scrim according to one of claims 7 to 11, characterized in that the cutting means (28) are designed as a movable knife or as a hot wire.

13. A device for producing a scrim according to one of claims 7 to 12, characterized in that the cutting means (28) is preceded by a transverse plastic tape coating station (21, 32) to a plurality of parallel plastic tape (la) fed in parallel to coat at least one of their surfaces with a plastic layer (lb).

14. A device for producing a scrim according to one of claims 7 to 13, characterized in that the connecting station is preceded by a longitudinal plastic tape coating station (15, 31) in order to have the plurality of parallel plastic tape (8) fed in parallel on at least one of them Coating surfaces with a plastic layer (16).

15. A device for producing a scrim according to claim 13 or 14, characterized in that the transverse plastic tape coating station (21, 32) and / or the longitudinal plastic tape coating station (15, 31) at least one nozzle (15a, 21a) for dispensing plastic melt and downstream press and coolant, preferably a pair of press and chill rolls (17, 18; 22, 23).

16. Device for producing a scrim according to one of claims 7 to 15, characterized by a plastic tape coating station (25) for producing a plastic web by coating a plurality of plastic tapes (la, 8) fed in parallel to one another with a plastic melt (27), and downstream thereof a separating device (26) for longitudinally separating the plastic web into a transverse web (1) and a longitudinal web (8a), deflection means (24) for feeding the transverse web (1) to the cutting and transfer means (2) are and the longitudinal path (8a) of the connecting station (6) can be fed.

17. scrim (11) made of plastic tapes, preferably polyolefin tapes, characterized by a structure of:

a plastic outer layer (1 b), a layer of transverse plastic tapes (la), which are preferably stretched, a plastic inner layer (10), and a layer of longitudinal plastic tapes (8), which are preferably stretched, and which are arranged at an angle, preferably approximately at a right angle, to the transverse plastic tapes (1a), the plastic inner layer (10) containing the layer of transverse plastic tapes (la) connects with the layer of longitudinal plastic tapes (8).

18. scrim (19) made of plastic tapes, preferably polyolefin tapes, characterized by a structure of:

a plastic outer layer (lb, 27), a layer of transverse plastic tapes (la), which are preferably stretched, a plastic inner layer (10), a layer of longitudinal plastic tapes (8), which are preferably stretched, and at an angle , preferably approximately at a right angle to the transverse plastic tapes (la), the plastic inner layer (10) connecting the layer of transverse plastic tapes (1 a) to the layer of longitudinal plastic tapes (8), and a further plastic Outer layer (16, 27).

19. scrim according to claim 17 or 18, characterized in that the cross-plastic tape layer from individual, one behind the other edge-to-edge arranged transverse web pieces (lc) from the plastic outer layer (lb, 27) interconnected plastic tapes (la) consists.

20. scrim according to one of claims 17 to 19, characterized in that a laterally beyond the longitudinal plastic ribbon (8) projecting end of the transverse plastic ribbon (la) is turned over and connected to itself or the longitudinal plastic ribbon (8) ,

21. clutch according to claim 17 or 18, characterized in that the plastic material for the plastic tapes (la, 8) and the individual plastic layers (lb, 10, 16, 27) made of polypropylene (PP), polyethylene (PE), in particular HDPE, LDPE or LLDPE, or their mixtures is selected.

22. clutch according to claim 21, characterized in that additives such as color batch, calcium carbonate, filler materials, UV protection agents etc. are added to the plastic material.

23. scrim according to one of claims 17 or 18, characterized in that the carrier material for the plastic tapes (la, 8) from film tapes, preferably mono- or coextruded film tapes, mono-extruded tapes, monofilaments such as monofilaments made of PET or polyamide (PA), and multifilament yarns is selected.

24. clutch according to claim 17 or 18, characterized in that it is produced according to the method according to any one of claims 1 to 6.