EP0742300B1 - Grid fabric made of polyester filament yarn, process and device for its manufacture - Google Patents

Abstract

Woven netting (1) made of polyester filament yarn, consisting of (A) polyester material with a high m.pt. and (B) copolymer with a low m.pt., the warp (2) and weft threads (3) being melted together with copolymer (B) at the crossover points (4) to prevent slippage. Both the warp threads and the weft threads are made of technical high-strength polyester filament yarn, one or both consist of materials (A) and (B), and the mesh spacing is 0.5-10 threads/cm. Also claimed is (i) a process for the prodn. of this netting and (ii) an appts. for this process.

Description

The invention relates to a mesh fabric made of polyester filament yarns, a procedure for the production of a mesh and an apparatus for performing this method.

A basic distinction must be made between such a grid fabric from a so-called full-area fabric. The mesh fabric tends to dissolve the already hardly pronounced Lattice strength at the crossing points between Warp and weft. The relaxed inner cohesion of the crossing thread layers causes the crossing points must be fixed.

A lattice fabric (1) made of polyester yarn, consisting of polyester material of high melting temperature and copolymer of low melting temperature, warp threads (2) and weft threads (3) of the lattice fabric (1) at the crossing points (4) are fused to one another by means of the copolymer in a sliding-resistant manner, and wherein the lattice division eg 3 threads per cm, where
the warp threads (2) and weft threads (3) made of the polyester material and the copolymer are known from FR-A-2 007 978.

It is also known from EP 0 359 436, polyester filament yarn to use which is made of higher polyester material Melting temperature and low melting temperature copolymer consists.

The polyester materials are at the crossing points fused together using the copolymer and formed in this way non-slip crossing points. The lattice structure Such a grid fabric therefore also remains Get shift.

Such mesh fabric is therefore quite suitable for Curtains. However, a problem of such mesh fabric arises by the fact that the glued intersection points burst, once the lattice weave is in the longitudinal direction of the filaments is charged.

The strength of such lattice fabrics can be increase by increasing the number of threads per unit length becomes. Then, however, there is the problem that none are delimited Adhesive areas are formed more. The grid fabric will then with increased strength overall to a flat structure merge. The grid function would then no longer apply.

Another way to fix the crossing points takes place in known grids by plastic wetting of the entire woven grid. The disadvantage is based that the plastic wetting also the warp threads or Includes weft threads outside the crossing points. Therefore not only the thread properties through the application of the permanent plastic, but it will additional wetting material is also required.

The object of the invention is therefore the known sliding To improve mesh fabric so that the lowest possible Grid divisions still delimited adhesive areas at the crossing points, which are also under the Influence of tensile forces less than those for tearing of the filaments are necessary tensile forces, do not burst.

This problem is solved in the known mesh fabric by the features of claim 1.

Under a lattice fabric is within the scope of the present Application understood a fabric, the thread density per unit length 0.5 - 10 threads per centimeter.

The advantage of the invention is that the fixed Connection between warp and weft on the common Crossing points is limited, and yet that neither disruptive influence on the thread properties still arises on any subsequent processing.

This advantage is achieved in that at least the Warp thread or the weft thread consists of a material mixture, one of which has a high material component Melting point and the other material component, - including copolymer called -, has a low melting point.

For polyester, for example, it is a melting temperature of approximately 257 degrees Celsius. Then in one Example and without limitation of the invention the low melting copolymer can be selected so that its melting point in the range between approx. 120 and 180 degrees Celsius lies. Because of the lower in relation to the polyester In any case, the melting point of the copolymer can be thermal Activation of the relevant threads in the crossing area between warp threads and weft threads without melting of the polyester would be feared.

By melting the copolymer portion is therefore in the area of the crossing points, solely by merging the copolymer a fixation between warp and weft occur. After cooling down the melted one Copolymers restore the original properties on. A disruptive influence on the given material properties is therefore excluded from this fixation procedure.

Another essential feature of the invention is that it it is enough for the desired strength, either only that Warp threads or only the weft threads made of polyester material and to provide the copolymer, but that in terms of strength properties is necessary both the warp threads as well as the wefts made of technical polyester filament yarn to manufacture.

This combination leads to the desired success. Here it can be assumed that the adhesive areas will burst at the crossing points in that when merging of the copolymer in the temperature range up to about 180 ° C a shrinking of the filament yarn starts, which also in the adhesive area.

If you put in such a shrunk filament yarn Longitudinal force, the shrinkage is reversed. Therefore the jointly melted area bursts in the area of the adhesive Material which makes the glue ineffective.

Through the use of high tenacity polyester filament yarns this destruction effect is countered. The jointly fused material can therefore both in the warp direction and the low elongation in the weft direction join the technical polyester filament yarns without closing burst.

Suitable yarns for this are so-called hybrid yarns (e.g. B. Hoechst AG, Frankfurt / Main). However, the use these yarns as filament yarns for the production of lattice fabrics not yet occurred.

Nevertheless, the mesh fabric according to this invention also always delimited with the planned grid divisions Form adhesive areas so that despite a tensile load still allows some stretch in the filament yarn will burst without the melted copolymer to let.

The present invention is therefore also fundamental to be distinguished from the use of two-component yarns for full-surface tissue. This is known, for example in plastic construction. There are two-component yarns as a matrix used, each of the components takes on certain strength properties / adhesive properties of the finished component. With this full-surface fabric, however, there is neither the need to fix the crossing points together, the different components still have an effect in terms of sliding resistance. With all-over tissue is already due to the relatively dense number of threads per unit length achieved a sufficiently sliding-resistant structure.

It should be expressly pointed out that the Invention is already realizable, if only either Warp or the weft with the properties mentioned above is provided. However, one use results in each of mixed yarn for both warp and weft, especially the use of identical blended yarns - at least with regard to the copolymer content -, to a further improve internal cohesion at the crossing points of the mesh.

Such mesh fabrics are preferred in technical Area in front, e.g. in filter construction, so at least for this Use case proposed the use of high-strength polyester yarns becomes.

Can be used to heat the pre-crossed mesh both non-contact heaters and contact heaters be used. The non-contact heating offers the advantage that a displacement of the pre-crossed mesh reliably avoided. However, we recommend for contact rollers further measures to prevent a premature postponement of the To prevent mesh. This will be discussed.

A major advantage of the invention is also based on the fact that a device suitable for manufacturing can be easily integrated into existing weaving machines. For this purpose, it is essentially proposed that the heating zone immediately after the weft insertion zone to prevent accidental displacement of the mesh prevent.

In one embodiment, the heater can be on fixed or piecewise carried radiant heater be. However, a heating roller is preferred to achieve this a continuous heating effect, while continuous Production of the mesh.

In any case, the development of the invention comes along subordinate heater to special importance. Considered one namely that usually such grids with subsequent impregnation to fix the lattice structure then be dried and a certain Subject to the influence of heat, known to the Shrinkage of the yarn is now thanks to this invention this heat shrink also anticipated, but this without the treatment step "impregnation".

The mesh fabric produced by this method can, however, in connection with downstream heating thermally so that the shrinking process already when winding up the melted at the crossing points Mesh fabric is finished.

The customer therefore receives a low-shrinkage mesh with the advantages of completely unproblematic aftercare. Therefore, this development of the invention comes Double function too. On the one hand, it becomes a safe to move Gluing of the crossing points in the mesh fabric achieved, while, on the other hand, those outside of the crossing points Yarns both lengthways and crossways can be shrunk to the final dimension.

Fig.1

ein erfindungsgemäßes Gittergewebe in schematischer Ansicht;

Fig.2

einen vergrößerten Kreuzungspunkt 4 des Gittergewebes nach Fig. 1;

Fig.3

eine Vorrichtung zur Herstellung eines Gittergewebes gemäß Fig. 1, 2;

Fig.4

eine vergrößerte Darstellung der Heizeinrichtung gemäß Figur 3.

The invention is explained in more detail below on the basis of exemplary embodiments. Show it:

Fig. 1

a grid fabric according to the invention in a schematic view;

Fig. 2

an enlarged crossing point 4 of the mesh fabric of FIG. 1;

Fig. 3

an apparatus for producing a grid fabric according to Fig. 1, 2;

Fig. 4

3 shows an enlarged illustration of the heating device according to FIG. 3.

Unless otherwise stated below, the following description always for all figures.

1 shows a mesh fabric 1. Such a mesh fabric 1 has a relatively low thread density per unit length. Depending on the thread thickness, there are usual thread densities between 0.5 to 10 threads per centimeter. It is easy imaginable that - due to the loose weave - the Slip resistance of such mesh fabric is practically missing. Around here, however, to come up with anti-slip equipment the crossing points 4 between the warp threads 2 and Weft threads 3 by thermal activation of the copolymer with each other merged. As shown in Fig.2 shows always a fused area in the area of the intersection points 4 5, in which the copolymer portions of the blended yarn penetrated between the filaments of the adjacent threads to cool down afterwards.

It is therefore another advantage of the invention that relatively good liquefaction when the copolymer is heated can take place, whereby a good penetration of the melted Copolymers between the individual filaments favored without the polyester properties of the other material be adversely affected.

This advantage is further enhanced if the Melting point of the copolymer based on the melting point of the Polyester material is removed as far as possible after Possibility of any undesirable temperature influence on the polyester material to prevent.

3,4 also show a corresponding device, in order to be able to carry out the present method. In a manner known per se, such mesh fabrics 1 made on weaving machines. This is done by a warp beam 7 or withdrawn from a creel 8 and a guided in a broad form over guide rollers. Of the the total of the warp threads drawn off is then every second Warp thread gripped and alternately under the thread sheet out of the first warp threads. In the making Gusset between the unfolded warp threads is now the Weft introduced. This is done in time with the subject within the weft insertion zone 9 of the weft across shot the constantly running warp threads.

Then, in a manner known per se, the so produced Mesh fabric fed to a winding tree 10. Of the Take-up boom 10 has a regulated rotational speed, to keep the longitudinal tension of the warp threads as constant as possible achieve. In such meshes there is always the problem that the wefts without tension and thus rest on the warp threads even without substantial friction. It it is therefore necessary that at least the winding process with the warp thread tension is as constant as possible.

It is now essential that immediately behind the intersection a heating device in the area of the weft insertion zone 9 11 is provided.

As can be seen in FIG. 4, there is such a heating device from a rotatingly driven heating roller 12. The Heating roller 12 is connected to a heating circuit. Want to achieve fast response times, it is recommended the heating roller e.g. to run as a steam-heated roller.

The heating roller of this type is now precrossed Lattice mesh wrapped at an angle of at least 180 degrees. As Fig.4 shows, the angle can also be considerable to be taller. For this purpose, two pressure rollers 13, 14 are used, which are under a certain pre-pressure force at the roller entry point 19 or roll outlet point 20 bear against the heating roller 12.

As can also be seen from FIG. 4, the deduction takes place the mesh fabric with a predetermined force F2. The Both pressure rollers 13, 14 therefore prevent slipping of the mesh fabric on the heating roller surface 12. Between the entry point 19 and the exit point 20 are formed area 21 where the pre-crossed is heated Mesh fabric can be done without displacement. To that extent can be in the decoupled area 21, the process of Melt the copolymer in the area of the crossing points lead safe to move.

3 shows that the heating device 11 a Includes temperature sensor 15, which is the current one Heating temperature measures. The measured is in a controller 16 Temperature compared with a predetermined target temperature. In any case, the target temperature is above the melting point of the copolymer, but below the melting point of the Polyester material. In the event of control deviations, the output signal of the controller via the operational amplifier 17 to one Control signal converted. The control signal is then the mixing valve 18 abandoned so that a closed regulation arises. If the heater 11 is a total of a steam heater fed, this offers the additional advantage faster reaction times in the event of control deviations anyway good heat transfer between heating medium and heating roller. It is therefore necessary for the most accurate process management possible to use quickly responding regulated heating circuit.

About the function:

The deduction of the warp thread sheet 8 leads this first of all in the area of the fold zone between the guide rollers where the weft entry takes place in a manner known per se. The warp threads are interwoven with the weft threads. As a result of the discipline movement, minimal pre-fixation can occur the weft threads are made in the warp threads.

While now the pre-woven grid continues towards Heating roller 12 is guided, it also passes through the area of upstream pressure roller 13 (see Fig. 4). There it will woven mesh deflected and towards the surface the heating roller 12 out. It passes through the roller inlet 19, where the warp threads have already been preheated with the weft threads be pressed. During the further circulation of the Heating roller 12 takes place a further heat transfer, whereby the copolymer melts so far in the area of the crossing points, that penetration of the melted Copolymers between the individual filaments of warp threads or weft threads. The penetration therefore leads to a intimate bond of the individual crossing filaments. Of the Verbund is based on the adhesive-fused copolymer.

Since the area between roll entry point 19 and roll entry point 20 is essentially strain relieved also not the risk that the premelted fabric structure is dissolved uncontrollably. When the melted ones approach Crossing points at the roller exit point 20, however they are pressed together again. This will melted copolymer intimately with the crossing filaments connected. However, since it is already sufficient, the least Add amounts of copolymer, or corresponding polyester yarns to be used with this non-slip version also no hardening of the crossing points. Especially if both the warp threads and the weft threads with the same If the copolymer is offset, you can create a mesh fabric that is easy to grip achieve without hard spots.

Claims (12)

1. Mesh fabric (1) of polyester yarn, consisting of polyester material of high melting temperature and copolymer of low melting temperature, wherein warp threads (2) and weft threads (3) of the mesh fabric (1) are fused together at the crossing points (4) by means of the copolymer to prevent sliding, and wherein the mesh distribution is in the range between 0.5 to 10 threads per cm, wherein

   1.1 both the warp threads (2) and also the weft threads (3) each consist of commercial polyester filament yarn with highly stable properties whose fineness strength is greater than 70 cN/tex, and

   1.2 out of the warp threads (2) and the weft threads (3) at least one of the two thread materials consists of the polyester material and the copolymer.
2. Mesh fabric according to claim 1, characterised in that the mesh distribution lies in the range between 1.5 and 4 threads per cm.
3. Mesh fabric according to one of claims 1 or 2, characterised in that the polyester filament yarn has a denier of more than 1000 dtex.
4. Mesh fabric according to one of claims 1 to 3, characterised in that warp threads (2) and weft threads (3) comprise the same copolymer.
5. Mesh fabric according to claim 4, characterised in that warp threads (2) and weft threads (3) consist of the same mixed yarn.
6. Method for the manufacture of a mesh fabric according to one of claims 1 to 5, wherein the mesh fabric (1) is preliminarily criss-crossed and the criss-crossed mesh fabric (1) is conducted past a heating device (11) immediately after the criss-crossing of the weft threads (3) by the warp threads (2), the heating device (11) is heated to a temperature above the melting temperature of the copolymer but below the melting temperature of the polyester material, and after the fusing on of the copolymer fixation is effected by pressure.
7. Method according to claim 6, characterised in that the heating is effected without contact.
8. Method according to claim 6, characterised in that the heating is effected at the same time as the fixing.
9. Apparatus for carrying out the method according to one of claims 6 to 8, consisting of a weaving machine, a warp beam (7), a weft thread entry zone (9) and a winding device (10) for the mesh fabric, wherein a heating zone with heating device (11) is arranged immediately following the weft thread entry zone, the heating device (11) can be heated to a temperature greater than the melting temperature of the copolymer but lower than the melting temperature of the polyester material, and a fixing zone with fixing device follows the heating zone.
10. Apparatus according to claim 9, characterised in that the heating device is a contact heater moving with the fabric.
11. Apparatus according to claim 10, characterised in that the heating device is a heated roller.
12. Apparatus according to claim 11, characterised in that roller entry and exit nip points (19 and 20) are defined by respective contact pressure rollers (13, 14), and the contact pressure force is at least sufficiently great that a neutral tension region (21) is created between roller entry nip point (19) and roller exit nip point (20).

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