EP3538707B1 - Fabric belt - Google Patents

Description

The present invention relates to a fabric belt for producing a web of corrugated cardboard in a corrugated cardboard machine.

State of the art

Corrugated cardboard machines have upper and lower belts that transport the corrugated cardboard through the corrugated cardboard machine. The upper warp layer of these fabric belts is in direct contact with the corrugated cardboard. It transports this through the corrugated cardboard machine with a certain amount of static friction and ensures that the corrugated cardboard is glued in a controlled manner. For this purpose, the fabric belt removes the moisture from the glue from the corrugated cardboard and releases it again at a later point in time.

The top belt transports the corrugated cardboard via heating plates, among other things. Edge areas of the upper belt which protrude beyond the width of the corrugated cardboard transported can come into contact with the heating plates. These can reach temperatures of up to 200 ° C. This results in thermal damage to the edge areas, which reduces the service life of the fabric belt. In addition, there is strong mechanical abrasion of the fabric belt in the edge areas.

From the WO 96/07788 A1 a fabric belt is known whose upper warp layer in the edge area only has warp threads which consist of aromatic polyamide fibers to which stainless steel fibers are optionally added. Such a fabric belt is able to withstand the high temperatures of the heating plates and the abrasion occurring there in its edge areas. However, the continuous polyamide fabric in the edge area prevents water from being absorbed into the fabric belt. This means that the edge areas of this belt cannot contribute to moisture management during the manufacture of corrugated cardboard.

In the WO 02/086231 A1 describes a fabric belt which has a material mixture with a fiber content of more than 30% of an aromatic polyamide on its entire paper side. The rest of the material mixture consists of polyester fibers and / or other carrier fibers. This fabric belt has increased wear resistance. However, it does not have any reinforcement in the particularly stressed peripheral areas.

It is therefore an object of the present invention to provide a fabric belt for a corrugated cardboard machine which is so temperature-resistant and abrasion-resistant in its edge areas that it can withstand contact with the heating plates and whose edge areas can also contribute to moisture management in corrugated cardboard production.

Disclosure of the invention

This object is achieved by a fabric belt for producing a web of corrugated cardboard in a corrugated cardboard machine which has several warp layers and which has a surface of its top warp layer with at least first areas and second areas in at least one edge area. The first areas consist of first yarns and the second areas consist of second yarns. The first yarns contain from 30% by weight to 100% by weight aromatic polyamides, and from 0% by weight to 70 wt% aliphatic and / or alicyclic polyamides and 0 wt% to 5 wt% other materials. The sum of the polyamides and other materials is 100% by weight. The second yarns contain 50 wt% to 85 wt% polyester and / or aliphatic polyamides and / or alicyclic polyamides. They also contain 15 wt% to 50 wt% cellulose. In addition, they can contain 0% to 5% by weight of other materials. The sum of the polyesters, polyamides, cellulose and other materials is 100% by weight. The cellulose is selected in particular from viscose, cotton, modal, lyocell and mixtures thereof. Viscose is preferred here because it has particularly good water absorption behavior due to its swelling behavior in length and thickness. The other materials can be metal fibers, for example, which give the at least one edge area antistatic properties. Carbon fibers can also be used for this purpose. It can also be provided that other materials are arranged in further areas in the at least one edge area. In order to maintain the antistatic properties, for example, third areas can be provided which only consist of metal fibers and / or carbon fibers.

The invention is based on the knowledge that it is not necessary to make the surface of an edge area from thermally and mechanically particularly resilient first yarns to increase the thermal resistance of the edge area to such an extent that it can withstand contact with the heating plates of a corrugated board system without significant damage can. Rather, it is sufficient to make the surface in the edge area only partially from the first yarns. This offers the possibility of providing second areas in addition to the first areas, which are second yarns with good water absorption capacity exhibit. This enables moisture management of the corrugated cardboard also in the edge area of the fabric belt.

The first areas preferably cover 1/6 to 5/6 of the surface of the at least one edge area. They particularly preferably cover 1/3 to 2/3 of the surface of the at least one edge area. The second areas preferably cover 1/6 to 5/6 of the surface of the at least one edge area. They particularly preferably cover 1/3 to 2/3 of the surface of the at least one edge area. They very particularly preferably cover the remaining surface, so that there are no other areas besides the first areas and the second areas. This ensures that, on the one hand, sufficient thermal stability of the edge areas is obtained so that they can withstand the thermal load caused by contact with heating elements of a corrugated board system and, on the other hand, a sufficiently large area of the surface is occupied by second yarns, the moisture from the belt surface in deeper can transport layers of fabric.

The second areas are preferably arranged on the surface in such a way that all second areas are connected to one another on the surface. This enables a particularly effective forwarding of absorbed moisture. The first areas here form islands that are enclosed by the second areas.

The width of each edge area is preferably in the range from 400 mm to 650 mm, particularly preferably in the range from 400 mm to 600 mm. This ensures that no areas of the fabric belt that are not designed as edge areas can come into contact with the heating plates of the corrugated board machine. Traditional fabric straps like her from the WO 96/07788 A1 are known, are often only designed with 200 mm wide edge areas, as these should be made as narrow as possible due to the lack of water absorption capacity of the edge areas. However, this can undesirably lead to regions of the fabric belt that are not thermally stable coming into contact with the heating elements. The improved water absorption capacity of the fabric belt according to the invention means that even significant portions of an edge area can be covered by corrugated cardboard without any problems, without problems with moisture management occurring. The configuration of the fabric belt according to the invention therefore makes it possible to make the edge areas wide, so that even when using narrow corrugated cardboard webs, a central area between the edge areas cannot be exposed.

The fabric belt is preferably designed in such a way that it has two edge regions, between which there is a central region. There are only second yarns on the surface of the upper warp layer of the central area. This means that the central area has a very good water absorption capacity. At the same time, the fabric belt is easy to manufacture, since yarns are used for the surface of its central area that are also used on the surface of the edge areas.

The central area in particular has a width in the range from 800 mm to 2,100 mm. This means that the fabric belt can be used in all common corrugated cardboard machines.

The first yarns and the second yarns are preferably made of staple fibers. Staple fiber yarns have the advantage over monofilaments and wires that they allow moisture to be absorbed between their fiber strands. With this, even the first yarns, which consist exclusively of non-water-absorbent materials, nor absorb a certain amount of water. The water absorption capacity of the second yarns is also improved by being made as staple fibers. It should be noted that only the cellulose content of the second yarn allows water to be absorbed by the fiber material. The polyesters and polyamides as synthetic yarn components, on the other hand, cannot absorb any water themselves. You can, however, enclose it in the execution as staple fiber yarns between their fiber strands and then pass it on to the cellulose.

The first yarns and the second yarns each have a preferred yarn count (effective denier) in the range from 1,000 dtex to 5,000 dtex, particularly preferably in the range from 2,000 dtex to 4,000 dtex. This can be achieved, for example, by twisting several single yarns with the preferred metric number (Nm) 20/2 to 20/10, particularly preferably 20/4 to 20/8. A definition of the denominations used can be found in the DIN 60910 standard. Such fiber fineness enables high abrasion resistance of the fabric belt in its edge area. In order to increase the abrasion resistance even further, it is preferably provided that the warp threads of the upper warp layer of the fabric belt consist of several first yarns or several second yarns with said yarn count.

The first yarns preferably contain at least 30% by weight of meta-aramid. This aromatic polyamide gives the yarns particularly good resistance. Meta-aramid has a lower modulus of elasticity than the polyester contained in the second yarns and the cellulose contained in the second yarns and is therefore more easily stretchable. It also has comparatively high abrasion resistance.

It is also preferred that the first yarns contain at least 10% by weight of para-aramid. This aromatic polyamide also has high thermal resistance. In contrast to meta-aramid, it is not stretchable due to its high modulus of elasticity. By suitably selecting the ratio between meta-aramid and para-aramid, the extensibility of the first yarns can be adjusted so that it essentially corresponds to the extensibility of the second yarns. This is important in order to give the edge area a uniform expansion behavior, which ideally also corresponds to the expansion behavior of the central area. In addition, para-aramid differs from all other materials used in the upper warp layer of the edge area in that it is colored. It gives the first areas a yellow color, thereby enabling a user to distinguish the peripheral areas from the central area.

The aliphatic and / or alicyclic polyamides of the first yarns are preferably selected from polyamide 6 and / or polyamide 66. These polyamides have a poorer thermal resistance than aromatic polyamides. However, in combination with the proportions of aromatic polyamides according to the invention, this is still sufficient to give the fabric belt sufficient thermal stability in its edge regions. At the same time, these materials are significantly cheaper than aromatic polyamides, which enables the fabric belt to be manufactured economically.

The inventive arrangement of the first areas and the second areas on the surface of the upper warp layer can in particular be achieved in that the warp threads of the upper warp layer of the at least one edge area consist of the first yarns and the second yarns.

The weft threads consist in particular of a polyester. However, they cannot absorb water in the polyester material. So that they can nevertheless make a small contribution to moisture management, it is preferred that the weft threads are staple fibers which still allow a certain amount of moisture absorption between their fiber strands.

In order to be optimally suitable for use in a corrugated cardboard machine, the fabric belt preferably has an upper warp layer, an inner warp layer, a lower warp layer, binding threads and two to four layers of weft threads. In this context, binding threads are understood to mean threads which connect all layers of weft threads to one another.

The binding threads consist in particular of the second yarns. They enable moisture to be transported from the upper warp layer to the lower warp layer. A moisture distribution that is as even as possible over the entire thickness of the belt accelerates the drying of the belt as it continues to circulate in the corrugated board machine.

The inner warp ply, which is enclosed by the upper warp ply and the lower warp ply, preferably has warp threads made of third yarns, which consist of polyester. The third yarns are particularly preferably multifilament yarns. These have a higher tensile strength than staple fiber yarns. In this way, they give the fabric belt the ability to absorb force in the inner warp layer by stretching the substance of the third yarn. The same yarn counts are preferred for the third yarns as for the first yarns and the second yarns.

Brief description of the drawings

Fig. 1

zeigt eine Aufsicht auf einen Gewebegurt gemäß einem Ausführungsbeispiel der Erfindung.

Fig. 2

zeigt eine Aufsicht auf die Oberfläche eines Randbereiches eines Gewebegurtes gemäß einem Ausführungsbeispiel der Erfindung.

Fig. 3

zeigt die Bindungspatrone des Randbereiches der oberen Kettlage eines dreilagigen Gewebegurtes gemäß einem Ausführungsbeispiel der Erfindung.

Fig. 4a

zeigt schematisch einen Stich bei der Herstellung des Randbereiches eines Gewebegurtes gemäß einem Ausführungsbeispiel der Erfindung.

Fig. 4b

zeigt einen anderen Stich bei der Herstellung des Randbereiches eines Gewebegurtes gemäß einem Ausführungsbeispiel der Erfindung.

Fig. 4c

zeigt noch einen anderen Stich bei der Herstellung eines Gewebegurtes gemäß einem Ausführungsbeispiel der Erfindung.

Fig. 5

zeigt einen schematischen Längsschnitt des Randbereiches eines Gewebegurtes gemäß einem Ausführungsbeispiel der Erfindung.

An embodiment of the invention is shown in the drawings and is explained in more detail in the following description.

Fig. 1

shows a plan view of a fabric belt according to an embodiment of the invention.

Fig. 2

shows a plan view of the surface of an edge area of a fabric belt according to an embodiment of the invention.

Fig. 3

shows the binding cartridge of the edge area of the upper warp layer of a three-layer fabric belt according to an embodiment of the invention.

Figure 4a

shows schematically a stitch in the production of the edge area of a fabric belt according to an embodiment of the invention.

Figure 4b

shows another stitch in the production of the edge area of a fabric belt according to an embodiment of the invention.

Figure 4c

Figure 10 shows yet another stitch in the manufacture of a fabric belt according to an embodiment of the invention.

Fig. 5

shows a schematic longitudinal section of the edge area of a fabric belt according to an embodiment of the invention.

Embodiment of the invention

A section of a fabric belt 1 that can be used as a top belt in a corrugated cardboard machine is shown in FIG Fig. 1 shown. This has a central area 11 and two edge areas 12, 13. The edge areas 12, 13 run parallel to the longitudinal direction 14 of the fabric belt 1. In the present exemplary embodiment, the central area 11 has a width Z of 800 mm and the edge areas 12, 13 each have a width R of 400 mm.

The fabric belt 1 is drawn into the middle of the corrugated cardboard machine as an upper belt and runs a maximum of +/- 0.5 cm in width. The corrugated cardboard runs under the belt, the corrugated cardboard edges should lie within the edge areas 12, 13. The upper warp layer of the fabric belt 1 points downwards and touches the corrugated cardboard.

The surface of the edge areas 12, 13 is in Fig. 2 shown. This has first areas 21 made of first yarns and second areas 22 made of second yarns. The second regions 22 are connected to one another in the form of a grid pattern in such a way that they separate the first regions 21 from one another. As a result, the first regions 21 form diamond-shaped "islands" which do not touch one another. In the present case, the first yarns are Nm 20/6 staple fiber yarns with an effective titer of 3,000 dtex, which contain 50% by weight meta-aramid, 35% by weight polyamide 66 and 15% by weight para-aramid. The second yarns are Nm 20/6 staple fiber yarns with a yarn count (effective denier) of 3,000 dtex, which contain 65% by weight of polyester and 35% by weight of viscose. The entire surface of the central area 11 consists only of the second yarns.

While the second yarns are raw white, the para-aramid content of the first yarns gives them a yellow color. The edge areas 12, 13 of the fabric belt 1 can therefore be distinguished optically from the all-over white central area 11 by a yellow-white pattern.

In the present exemplary embodiment, the fabric belt 1 is designed as a three-layer fabric. An excerpt from the report of his binding cartridge is in Fig. 3 shown. He has twelve shots 301-312. The base chains are guided in 14 shafts 401-414, with only the upper base chain, which runs in the shown shafts 411-414, being relevant for the formation of the first regions 21 and the second regions 22 on the surface of the edge regions 12, 13.

The indentation which is used to achieve the patterning of the edge areas 12, 13 with the first areas 21 and the second areas 22 is for the shafts 401-414 in FIG Figures 4a to 4c shown. The first yarns 51 are only used in the shafts 411-414. The second yarns 52 are used in the shafts 401-408 and 411-414. Third yarns 53 are used in the shafts 409 and 410. These are polyester multifilament yarns with a yarn count of 3,300 dtex. In the shafts 401-404 and 409-410 two threads of the in the Figures 4a to 4c designated yarn n passed through the strands that are strung in the shafts. In the shafts 405-408 and 411-414, three threads of the designated yarns are passed through the strands. The first stitch is done according to Figure 4a on the rear heald bar of the loom used. The second stitch is done according to Figure 4b on the front stranded rod. The third trick is done accordingly Figure 4c on the rear stranded rod. The fourth stitch is done accordingly Figure 4a on the front stranded rod. The fifth trick is done accordingly Figure 4b on the rear stranded rod. The sixth trick is done accordingly Figure 4c on the front stranded rod. These six stitches are repeated until the desired width of the edge areas 12, 13 is reached. As a result, a fabric is obtained in the edge regions 12, 13, the uppermost warp layer of which consists of one third of the first yarns 51 and two thirds of the second yarns 52 on its surface.

A longitudinal section of one of the edge regions 12, 13 is shown in FIG Fig. 5 shown. There, the warp threads and binding threads of the fabric are denoted by the same reference numerals that are used in the Figures 4a to 4c were used for the respective shafts in which they are guided. In addition to the warp threads and binding threads, the weft threads 6 are also shown. It can be seen that the fabric has three warp layers 71, 72, 73. In the upper warp layer 71, which has the first areas 21 and the second areas 22 on its surface, four mutually offset warp threads 411-414 are provided, which cross both inwards towards the inner warp layer 72 and outwards towards the paper side at least two weft threads 6 run. There are warp threads 411-414 as shown in FIG Figures 4a to 4c one third of the first yarn 51 and two thirds of the second 52. The inner warp layer 72 has two warp threads 409, 410 running offset to one another, which consist of the third yarns 53 and each run over two weft threads 6. The lower warp layer 73 consists of four warp threads 405 - 408, each running offset to one another, which run inward, that is to say towards the inner warp layer 72, over only one weft thread 6 and outward over at least three weft threads 6. The warp threads 405-408 of the lower warp layer 73 consist of second yarns 52. The three warp layers 71, 72, 73 are interwoven via binding threads 401-404. The binding threads are each divided into two thread groups, the binding threads 403, 404 forming a thread group running offset to one another and binding the upper warp layer 71 with the inner warp layer 72. These binding threads 403, 404 are each guided alternately around a weft thread 6 in the upper warp layer 71 and a weft thread 6 in the inner warp layer 72. In a corresponding manner, the thread group formed from the binding threads 401, 402 binds the lower warp layer 73 to the inner warp layer 72. All weft threads 6 consist of polyester staple fiber yarns. A "thread" is understood in the foregoing to mean a bundle of several threads which consists of two threads for the binding threads 401-404 and for the warp threads 409-410 of the inner warp layer 72 and for the warp threads 405-408 of the lower warp layer 73 and the Warp threads 411-414 of the upper warp layer 71 each consist of three threads. Only the weft threads 6 each consist of only one thread.

When a corrugated cardboard machine is in operation, portions of the edge regions 12, 13 not covered by the web of corrugated cardboard are temporarily exposed to the heating plates of the corrugated cardboard machine. Thermal and mechanical damage to the edge regions 12, 13 is prevented by the first regions 21, which consist of the first yarns 51. The sections of the edge areas 12, 13 which cover the corrugated cardboard absorb water and water vapor from the web of corrugated cardboard as part of moisture management. In this case, water can be absorbed between the staple fibers both by the first yarns 51 and by the second yarns 52. In addition, the viscose portion of the second yarns 52 can absorb up to 80% of its own weight in moisture. In this way, the edge regions 12, 13 of the fabric belt 1 fulfill a hybrid function of thermal and mechanical protection and moisture management.

Claims (15)

1. Fabric belt (1) for the production of a corrugated cardboard web in a corrugated cardboard machine having several warp layers (71, 72, 73), wherein a surface of its upper warp layer (71) has at least first regions (21) which consist of first yarns (51), and second regions (22) which consist of second yarns (52), wherein

   - the first yarns (51) contain 30% b.w. to 100% b.w. aromatic polyamides, 0% b.w. to 70% b.w. aliphatic and/or alicyclic polyamides and 0% b.w. to 5% b.w. other materials, wherein the total of the polyamides and other materials gives 100% b.w., and

   - the second yarns (52) contain 50% b.w. to 85% b.w. polyester and/or aliphatic polyamides and/or alicyclic polyamides, 15% b.w. to 50% b.w. cellulose and 0% b.w. to 5% b.w. other materials, wherein the total of the polyesters, polyamides, cellulose and other materials gives 100% b.w.,

   characterised in that in at least one edge region of the fabric belt, a surface of its upper wrap layer has at least first regions and second regions.
2. Fabric belt (1) according to claim 1, characterised in that the first regions (21) cover 1/6 to 5/6 of the surface of the at least one edge region (12, 13) and the second or more regions (22) cover the rest of the surface.
3. Fabric belt (1) according to claim 1 or 2, characterised in that the width (R) of each edge region (12, 13) ranges from 400mm to 650mm.
4. Fabric belt (1) according to one of claims 1 to 3, characterised in that it has two edge regions (12, 13), between which a central region (11) is located which only has second yarns (52) on the surface of its upper warp layer.
5. Fabric belt (1) according to claim 4, characterised in that the central region (11) has a width (Z) in the range from 800mm to 2,100mm.
6. Fabric belt (1) according to one of claims 1 to 5, characterised in that the first yarns (51) and the second yarns (52) are staple fibre yarns.
7. Fabric belt (1) according to one of claims 1 to 6, characterised in that the first yarns (51) and the second yarns (52) respectively have a yarn count in the range from 1,000 dtex to 5,000 dtex.
8. Fabric belt (1) according to one of claims 1 to 7, characterised in that the first yarns (51) contain at least 30% b.w. meta-aramid.
9. Fabric belt (1) according to one of claims 1 to 8, characterised in that the first yarns (51) contain at least 10% b.w. para-aramid.
10. Fabric belt (1) according to one of claims 1 to 9, characterised in that the aliphatic and/or alicyclic polyamides of the first yarns (51) are selected from PA6 and/or PA66.
11. Fabric belt (1) according to one of claims 1 to 10, characterised in that the warp threads (411, 412, 413, 414) of the upper warp layer (71) consist of the first yarns (51) and the second yarns (52).
12. Fabric belt (1) according to one of claims 1 to 11, characterised in that it has an upper warp layer (71), an inner warp layer (72), a lower warp layer (73), binding threads (401, 402, 403, 404) as well as two to four layers of weft threads (6).
13. Fabric belt (1) according to one of claims 1 to 12, characterised in that it has binding threads (401, 402, 403, 404) which consist of the second yarns (52).
14. Fabric belt (1) according to one of claims 1 to 13, characterised in that an inner warp layer (72) has warp threads (409, 410) made from third yarns (53) which consist of polyester.
15. Fabric belt (1) according to claim 14, characterised in that the third yarns (53) are multifilament yarns.

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