PROCESS AND DEVICE FOR SPLITTING A TAPE

Abstract

A process and a splitter for splitting a tape of a uniaxially oriented material. The tape is passed in a process direction over a static splitting profile having a row of teeth, e.g., with a cutting edge extending in the process direction. The tape is split to form a material comprising a plurality of parallel strips interconnected by fibrils. The split material can for example be used for the production of high tensile ropes or laminates.

Claims

1. A process of splitting a tape of a uniaxially oriented material, wherein the tape is passed in a process direction over a static splitting profile having a row of teeth splitting the passing tape into a material comprising a plurality of parallel strips interconnected by fibrils, the fibrils having a width which is smaller than a width of the strips.

2. The process of claim 1, wherein the teeth are parallel, each one of the teeth having a cutting edge extending in the process direction.

3. The process of claim 1, wherein the teeth are triangular in cross section perpendicular to the process direction.

4. The process of claim 2, wherein the cutting edges of each of the teeth define a circle or circular segment, the teeth being coaxially arranged.

5. The process of claim 1, wherein the tape passes the splitting profile with a processing speed of at least 1 m/min, e.g., up to about 100 m/min.

6. The process of claim 1, wherein the tape is fed to the splitting profile with an entrance angle of 0-90 degrees to the horizontal.

7. The process of claim 1, wherein the tape is fed to the splitting profile with an exit angle of 0-90 degrees to the horizontal

8. The process of claim 1, wherein the uniaxially oriented material is polyethylene.

9. The process of claim 1, wherein the uniaxially oriented material is UHMWPE.

10. A process for the production of a rope, wherein a tape of a uniaxially oriented material is split into a plurality of strips interconnected by fibrils, and wherein the strips are subsequently twisted to form the rope.

11. A uniaxially oriented material having a direction of uniaxial orientation and comprising a plurality of parallel strips with sides extending parallel to said direction of uniaxial orientation, the strips being interconnected by fibrils, the fibrils having a width which is smaller than a width of the strips, with one of said strips bordering one longitudinal side edge of the material and another one of said strips bordering an opposite longitudinal side edge of the material.

12. The material of claim 11, the plurality of parallel strips having a width of 0.25-5 mm and the fibrils having a width below 0.25 mm.

13. A laminate comprising a foil layer and a layer at at least one side of the foil layer, wherein the layer is formed by laminating at least one layer of a material according to claim 11.

14. A rope comprising one or more twisted materials according to claim 11.

15. A splitter for splitting tapes of a uniaxially oriented material, the splitter comprising a splitter profile, a tape feeder for feeding tape to the splitter profile in a process direction, the splitter profile having a row of teeth which are triangular when viewed in the process direction, having a fixed position and orientation relative to the tape feeder.

16. The splitter of claim 15, each one of the teeth having parallel cutting edges for engaging and splitting the tape, said cutting edges extending in the process direction.

17. The splitter of claim 15, further comprising a counter profile, wherein the splitter profile and the counter profile form a nip for passage of the tapes, the counter profile having teeth intermeshing with the teeth of the splitter profile.

Description

[0040] The invention is further explained with reference to the accompanying drawings.

[0041] FIG. 1A: shows in front view an exemplary embodiment of a splitter;

[0042] FIG. 1B: shows the splitter of FIG. 1A in side view;

[0043] FIG. 1C: shows in front view a second exemplary embodiment of a splitter;

[0044] FIG. 1D: shows the splitter of FIG. 1C in side view;

[0045] FIG. 1E: shows in front view a third exemplary embodiment of a splitter;

[0046] FIG. 1F: shows the splitter of FIG. 1E in side view;

[0047] FIG. 2A: shows an arrangement with the splitter of FIG. 1A in top view during a splitting process;

[0048] FIG. 2B: shows the arrangement of FIG. 2A in side view;

[0049] FIG. 3: shows in top view a laminate comprising processed tape material;

[0050] FIG. 4: shows the laminate in side view.

[0051] FIGS. 1A and 1B show a splitter 1 for splitting UHMWPE tapes, or tapes of a similar high tensile strength material, to form strips interconnected by fibrils, e.g., for twisting a high tensile rope. The splitter 1 comprises a profile 3 and a counter profile 5. The profile 3 and the counter profile 5 are parallel and have teeth 6 with cutting edges 7. The teeth 6 are triangular when viewed in a direction perpendicular to a longitudinal axis X of the profile 3. The teeth 6 of the counter profile 5 intermesh with those of the profile 3 to form a zig-zag nip 10 for passage of the tapes. The tapes pass the nip 10 in a process direction A perpendicular to the plane of the drawing in FIG. 1 (see FIG. 2). The cutting edges 7 extend in the process direction A, at least at the position of the nip 10.

[0052] In the shown embodiment the profile 3 and the counter profile 5 are two parallel mainly cylindrical bodies. However, the profile 3 and counter profile 5 may have any other suitable shapes, provided that they define a zig-zag nip between intermeshing triangular cutting edges. The profile 3 and the counter profile 5 are static, so they have a fixed position and orientation and do not rotate during the process.

[0053] FIGS. 1C and 1D show an alternative splitter 101 with teeth 106 only at and near the position of the zigzag nip 110. A similar embodiment 201 is shown in FIGS. 1E and 1F, having intermeshing teeth 206 only at the position of the nip 210. The profile 203 and the counter profile 205 have rectangular cross sections. Since the profile and the counter profile are static and do not rotate, they can have any cross section.

[0054] FIG. 2A shows in top view how a tape 12 of a uniaxially oriented material is fed from a tape feeder 11 is guided via the splitter 1 of FIGS. 1A and 1B. The cutting edges 7 of the teeth 6 of the profile 3 and the counter profile 5 split the tape 12 into a plurality of parallel strips 13. These strips 13 are not completely separated but are still interconnected by individual fibrils 14, as is shown in FIG. 3, showing the split material in a flat and unfolded condition, embedded in a matrix to form a laminate 15.

[0055] As is shown in FIG. 3, the fibrils 14 have a width which is smaller than a width of the strips 13. One of the strips 13A borders a longitudinal side edge of the material and another strip 13B borders an opposite longitudinal side edge of the material. The strips 13A, 13B bordering the two longitudinal side edges of the material are connected to an adjacent strip 13 by fibrils 14 at only one of their respective sides, while all other strips 13 connect to interconnecting fibrils 14 at both sides.

[0056] The strips 13 have a flat cross section with a width of 0.25-5 mm, whereas the fibrils 14 have a thread-like cross section and an average diameter below 0.25 mm.

[0057] The split tape material 12 can for example be used in a laminate 15, as is shown in FIGS. 3 and 4. The laminate 15 comprises a foil layer 16 and layer 17 formed by the split tape material 12. The split tape material 12 is spread to increase the distance between the individual strips 13 of the split tape material 12. The foil carrier may for instance be an LDPE or HDPE layer. The split tape material 12 can be laminated at a temperature just above the melting temperature of the foil carrier but below the melting temperature of the tape material. The laminate can have more layers formed by one or more split tape materials, e.g. between the enforced layer and the foil and/or on top of the foil and/or on top of the tape-reinforced layer. Such laminates have a high impact resistance.