KR20140115300A - Rope comprising at least one fibrillated film tape - Google Patents

Abstract

The present invention is directed to a method of making a tape (10) comprising the steps of: (i) providing a uniaxially oriented tape (10) comprising ultrahigh molecular weight polyethylene having a tensile strength of at least 0.9 GPa; and Simultaneously twisting and fibrillating with a twisted strand of a fibrillated tape having a network of fibers to produce a high strength rope. Ropes obtainable by this method and articles comprising such ropes are also disclosed.

Description

A rope comprising at least one fibrillated film tape (ROPE COMPRISING AT LEAST ONE FIBRILLATED FILM TAPE)

The present invention relates to a method of making a high tensile strength rope comprising at least one strand comprising an uniaxially oriented elongated body comprising ultra high molecular weight polyethylene.

Such a rope is known from U.S. Patent No. 5,901,632. The patent publication discloses a large-diameter braided rope containing a primary strand of a secondary strand, preferably containing a high tensile strength uniaxially oriented ultra-high molecular weight polyethylene filament. . In the most preferred embodiment specified, the rope is a twelve-strand, two-over / two-under circular braid, wherein each strand is itself a high-elasticity polyethylene HMPE) filament (12x12 structure).

These ropes, especially when made from high tenacity fibers, have high longitudinal deformations that make them especially suitable for load bearing applications, even when high extensional forces are applied longitudinal deformation resistance.

Nevertheless, such a rope is not subjected to axial compression, non-extension forces such as a transverse or rolling force applied in a crosswise fashion to the bending force or its longitudinal direction (non -extensional force is applied in the other direction. When exposed to a frequent non-extensional force, the rope is broken due to rope and filament damage resulting from external and internal abrasion, frictional heat, or fatigue, for example. Can be. Additionally, axial compression fatigue caused by buckling and kinking in the strand is observed when the rope undergoes an excessive number of axial compressions, such as rotation at low tension . No other solution has been proposed other than avoiding the condition of the rope cycle in the storage force to improve the axial compression fatigue (ref. P. 171 ff and 353 of the Handbook of fiber rope technology (eds. McKenna, Hearle and O'Hear, Woodhead Publishing Ltd, ISBN 1 85573 606 3).

It is an object of the present invention to provide a method of manufacturing a rope having properties optimized for the above-mentioned defects.

According to the present invention, this object is solved by a process for producing a mono-axially oriented ultra-high molecular weight polyethylene tape having a tensile strength of at least 0.9 GPa as measured according to ISO 1184 (H) And twisting and fibrillating simultaneously with twisted strands of fibrillated tape having a coherent network.

Surprisingly, it has been observed that the process of the present invention provides a rope that can have optimized stability against non-extensional deformational forces.

The present invention also relates to a rope obtainable by the process of the present invention.

The rope according to the present invention may have a round cross-section, for example a substantially circular cross-section or an oblong cross-section. Rectangular-section means here that the cross section of the rope is flat, elliptical, or flat and almost rectangular in shape. Such a rectangular cross section preferably has an aspect ratio in the range of 1.2 to 4.0, that is, a ratio of the width to the height of the cross section. Methods for measuring aspect ratios are known to those skilled in the art; For example, maintaining the rope tightly, or tightly winding the adhesive tape around the rope and then measuring the outside dimensions of the rope. The advantage of a rectangular cross-section with such aspect ratio is that less stress difference may occur between fibers in the rope, while the cross-section of the cross-section is bent in an annular fashion parallel to the transverse direction of the sheave. In addition, for certain applications, wear and frictional heat can be less and bend fatigue life can be improved. The cross section preferably has an aspect ratio of about 1.3 to 3.0, more preferably about 1.4 to 2.0.

Preferably, the fibrillated tape in the rope and / or rope is coated with a coating to improve various properties such as abrasion resistance or flexural fatigue. Such coatings, which can be applied on fibrillated tapes prior to rope fabrication, or on ropes after rope fabrication, are known, examples of which include silicone oil, bitumen, and a coating comprising both . Polyurethane based coatings that can be mixed with silicone oil are also known. The rope preferably contains an amount of coating of from 2.5 to 35 wt% as expressed by the weight of the coating relative to the total weight of the rope. More preferably, the rope contains an amount of coating of from 5 to 15 wt%.

A rope is understood herein as a long assembly of at least one strand. The strand may also include one or more sub-strands, commonly referred to as secondary strands. Each strand or secondary strand may comprise at least one fibrillated tape as used in accordance with the present invention.

In a preferred embodiment, the rope of the present invention comprises at least one strand comprising a fibrillated tape.

In another preferred embodiment, all strands of the rope of the present invention comprise a fibrillated tape.

In another preferred embodiment, the at least one strand of the rope of the present invention comprises a secondary strand comprising a fibrillated tape.

The ropes according to the present invention may have a variety of structures, including laid, braided, plaited or parallel structures, with or without cores. The number of strands in the rope can also vary greatly. The parallel rope may comprise at least a single strand. The number of strands in a more complicated rope structure may be at least three and preferably no more than 50, more preferably no more than 25 in order to reach a combination of good performance and ease of manufacture.

In a preferred embodiment, the rope according to the present invention may be a braided structure. Braiding provides a robust and torque-balanced rope that maintains its consistency during use. In general, various types of braids, which are distinguished by the method of braiding, are known. Suitable structures include decorative squeach braids, tubular braids, and flat braids. Tubular or circular braids are the most preferred braids for rope applications and generally consist of two sets of intertwined strands which may have different patterns. The number of strands in the tubular braid can vary widely. Especially when the number of strands is large and / or the strands are relatively thin, the tubular braid may have a hollow core; The braid can collapse into a rectangular shape. The number of strands in the braid rope according to the present invention is preferably at least four. There is no upper limit on the number of strands, but in practice the rope will generally have no more than 48 strands. A rope having an 8- or 12-strand braid structure is particularly suitable. These ropes provide a positive combination of toughness and resistance to bending fatigue and can be economically manufactured on relatively simple machines.

The rope according to the invention may also be a raid structure with a lay length, at which time the length of one turn of the strand in the lay structure, or the braiding period, The pitch length of the braid rope is in the range of 4 to 20 times the rope diameter. Larger lay lengths or braiding cycles can result in ropes with higher strength efficiencies. The ray length or the braiding period is preferably about 5 to 15 times the rope diameter, more preferably 6 to 10 times the rope diameter.

The structure of the strands of the rope according to the invention may also be a raid, braid or twisted strand.

In one embodiment of the present invention, at least one strand is a braided rope, and more preferably all strands are braided ropes. Preferably, the strand is a circular braid made from far more secondary strands comprising fibrillated tape. The number of many secondary strands forming the braided rope strand is not limited, but may be, for example, from 4 to 32; From the viewpoint of the machine useful for manufacturing such a braid, 8, 12 or 16 are preferable.

The uniaxially oriented ultra-high molecular weight polyethylene tape suitable for making the fibrillated tape can be prepared by drawing the film. The film is obtained by feeding ultra-high molecular weight polyethylene (UHMWPE) powder between a combination of endless belts, compressing the UHMWPE powder at a temperature below its melting point, rolling the resulting compression- ≪ / RTI > Another preferred process for forming the film comprises feeding the UHMWPE powder to an extruder, extruding the film at a temperature above the melting point of the powder, and stretching the extruded polymer film. In some cases, the polymer may be mixed with a suitable liquid organic compound to form a gel, for example, as in the case of using ultra high molecular weight polyethylene, prior to feeding the polymer to an extruder.

The process of stretching the film, preferably uniaxially stretching it, may be carried out by using means known in the art. Such means include extrusion and stretch stretching on suitable stretching apparatus. In order to increase mechanical strength and stiffness, the stretching can be carried out in a number of steps.

The tape used in the present invention obtains a material uniaxially oriented by stretching orientation at a suitable temperature, for example. By uniaxially oriented tape it is meant in the context of the present application that the tape exhibits a preferred orientation of the polymer chains in one direction, i. E. In the stretching direction. Such tapes will exhibit anisotropic mechanical properties.

The resulting stretch tape can be used as in a rope production process, or they can be cut or split to a desired width. Preferably, such splitting may be carried out along the stretching direction.

The width of the tape is limited only by the width of the film that produces them. The width of the tape used to produce the rope is preferably at least 2 mm, more preferably at least 5 mm, and most preferably at least 30 mm. The area density of such tapes may vary over a wide range, for example in the range of 2 to 200 g / m < 2 >. The preferred areal density is in the range of 10 to 170 g / m 2, more preferably in the range of 10 to 100 g / m 2, and most preferably in the range of 20 to 60 g / m 2. The increased stability to non-stretch stresses can be achieved by tapes within the preferred ranges described above.

The linear density of the strands of the fibrillated tape of the present invention can vary within a wide range and can be selected according to the final linear density of the rope as well as the number of fibrillated tapes in the strand. Linear density is measured by measuring the weight (mg) of a 10-meter long material and is conveniently expressed in dtex (g / 10 km) or denier (den, g / 9 km). The linear density of the fibrillated tape may depend on the area density of the tape, the width of the tape, and the twist level of the fibrillated tape. Thus, the reduced width of the tape used to make the fibrillated tape, the reduced area density of the tape, or the higher twist level of the fibrillated tape provides a lower linear density of the fibrillated tape While the increased width of the tape, the increased areal density of the tape, or the reduced twist level of the fibrillated tape can provide a higher linear density of the fibrillated tape. The linear density of the fibrillated tape of the rope in the present invention will preferably be in the range of 400 dtex (360 denier) to 200000 dtex (180000 denier). More preferably, the linear density of the fibrillated tape is in the range of 1000 dtex (900 den) to 100000 dtex (90000 den), even more preferably 2000 dtex (1800 den) to 50000 dtex (45000 den) It will be in the range of 5000 dtex (4500 denier) to 20000 dtex (18000 denier). The stability to non-stretch stresses can be further optimized by a tape having a linear density within the preferred range described.

The tape provided by the process of the present invention comprises ultra high molecular weight polyethylene (UHMWPE). The ultra high molecular weight polyethylene may be linear or branched, but preferably linear polyethylene is used. Linear polyethylene is understood herein to mean polyethylene having less than 1 side chain per 100 carbon atoms, preferably less than 1 side chain per 300 carbon atoms; Wherein the side chain or branch generally contains at least 10 carbon atoms. The side chain can be suitably measured by FTIR on a 2 mm thick press-molded film, for example, as specified in EP 0269151. The linear polyethylene may further contain up to 5 mol% of one or more other alkenes copolymerizable therewith, for example, propene, butene, pentene, 4-methylpentene, octene. The linear polyethylene has an intrinsic viscosity (IV) of preferably at least 4 dl / g, more preferably at least 8 dl / g and most preferably at least 10 dl / g (measured in solution in decalin at 135 ° C) With a high molar mass. Such polyethylenes are also referred to as ultra high molecular weight polyethylene (UHMWPE). The intrinsic viscosity is a measure of the molecular weight that can be measured more easily than a substantial molar mass parameter similar to Mn and Mw.

The rope according to the present invention may further comprise elongated bodies such as a tape, a yarn and / or a filament. These additional elongated bodies can be made from polyolefins, polyesters, polyvinyl alcohols, polyacrylonitriles, polyamides, especially poly (p-phenylene terephthalamides), liquid crystal polymers and ladder-like polymers such as polybenzimidazole or Polybenzoxazole, especially poly (1,4-phenylene-2,6-benzobisoxazole), or poly (2,6-diimidazo [4,5- b-4 ', 5'- Pyridinylene-1,4- (2,5-dihydroxy) phenylene). The additional stretch preferably comprises UHMWPE according to one of the tapes used in the present invention.

The tensile strength of the tapes prior to the fibrillation process depends on the UHMWPEs they produce, and their (uniaxial) stretch ratios. The tensile strength of such tapes is at least 0.9 GPa, preferably at least 1.2 GPa, more preferably at least 1.5 GPa, even more preferably at least 1.8 GPa, even more preferably at least 2.1 GPa, most preferably at least 3 GPa to be.

The ropes according to the invention are particularly useful for a variety of uses such as mooring, towing, lifting, and coastal facilities.

The rope according to the present invention may also be used for fishing rope, fishing net, cargo net, cargo curtain, belt, fabric, raschel and sling, ), ≪ / RTI > as well as in other applications such as < RTI ID = 0.0 > Thus, the present invention also relates to the uses enumerated above containing the rope of the present invention.

One embodiment of the present invention comprises the steps of providing a uniaxially oriented tape comprising ultrahigh molecular weight polyethylene having a tensile strength of at least 0.9 GPa as measured according to ISO 1184 (H), and providing said tape to a filament and a fibril And simultaneously twisting and fibrillating the twisted strands of the fibrillated tape with the entangled network to a process for producing the rope. In the context of the present invention, the term fibrillization refers to providing a tape having a plurality of confined slits in the machine direction of the tape, the rows of which are arranged laterally with respect to each other. Fibrillation occurs during twisting of the uniaxially oriented tape and as a result of the mechanical treatment of the tape. Fibrillization may also occur partially, for example after twisting steps during transfer, coiling and / or extruding, as well as after uniaxially oriented tape occurs before and during the twisting step, such as during processing and supply of twisted tape It is possible. Suitable twisting devices are those devices commonly used to process continuous filaments or staples into yarns and will be well known to those skilled in the art.

The process according to the invention may further comprise post-stretching a rope comprising twisted strands of fibrillated tape and / or twisted strands of fibrillated tape have. This post-stretching step is preferably carried out at a temperature below the melting point of the (lowest melting point) fibrillated tape in the strand (heating-drawing). For ropes containing fibrillated tapes containing UHMWPE, the preferred temperature is in the range of 100 to 120 占 폚. Such a heat-stretching step is described in EP 398843 B1 or US 5901632.

The invention will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of a plan view of a fibrillated tape when twisted fibrillated tape is spread over a flat fibrillated tape.

In accordance with the present invention, the fibrillated tape 10 comprises a plurality of longitudinal slits 20. The slits 20 may have irregular lengths and numbers. Individual distances in the width direction of the tape between adjacent slits may also have irregular sizes.

The fibrillated tape may exhibit a net-like structure comprising filaments 12 and fibrils 14 when unfolded. The filaments 12 and fibrils 14 are not continuous but can be interconnected. The fibrillated tape may be an interconnected web with additional, interconnected filaments forming a highly consistent yarn-like product with the appearance or fibril of the loosely focused continuous filament yarn. As shown in Fig.

In the context of the present invention, the terms filament and fibril are both considered to represent stretches which are segments of the tape. The elongate bodies (filaments and fibrils) are delimited in their width direction by two adjacent slits 22 or by one slit and one edge of the tape 24.

The filaments 12 are such elongate bodies interconnected with a net-like structure of the fibrillated tape by their two opposite ends 16. The fibrils 14 are such elongated bodies interconnected with the net-like structure by one of their ends 16. Briefly, fibrils are dangling filaments.

The dimensions, e.g., width and length, of the filaments and fibrils will depend largely on the dimensions of the tape used as well as the fibrillating process. The length of the filament is defined by the distance between two successive ends when the filaments are interconnected with the net-like structure, and can vary widely in the range of 1 to 1000 mm. Preferably, the filament is provided having a length of 2 to 500 mm, more preferably 4 to 200 mm, and most preferably 10 to 100 mm by adjusting the fibrillation process. The length of the fibril is defined as the distance between the end of the fibril that is interconnected with the net-like structure and its opposite end, and can vary widely in the range of 1 to 1000 mm. Preferably, the fibrillation process is adjusted to provide fibrils having a length of from 2 to 500 mm, more preferably from 4 to 200 mm, and most preferably from 10 to 100 mm.

The thickness of the filament or fibril may be substantially equal to the thickness of the tape used. The width of the filaments or fibrils defined by the distance between two adjacent slits forming filaments or fibrils can vary widely, preferably in the range of 20 to 20 mm. The width of the fibrils or filaments is preferably 40 占 퐉 to 5 mm, more preferably 80 占 퐉 to 2 mm, and most preferably 100 占 퐉 to 1 mm. In a preferred embodiment of the present invention, the filaments and fibrils may have a substantially rectangular cross-section.

In a preferred embodiment, the process of the present invention provides a twisted strand comprising a fibrillated tape having a twist level in the range of 1 to 100 turns per meter (tpm). The level of twist is preferably 2 to 80 tpm, more preferably 5 to 50 tpm, most preferably 10 to 35 tpm.

In another preferred embodiment, the process of the present invention comprises braiding, laying, twisting or bundling at least one twisted strand comprising a fibrillated tape to a rope the method comprising the steps of:

In alternate embodiments of the process of the present invention, the uniaxially oriented tape is provided in a package. In the context of the present invention, such packages may include storage of certain suitable forms of uni-oriented tape, such as bobbins, rolls, continuous ribbon containers, and the like. If uniaxially oriented tape is provided by unwinding the tape from the package, such unwinding is preferably carried out by peeling the tape upward from the fixed package. The term fixation means that in the context of the present invention the package does not substantially rotate about its helical axis. Optionally, the package may move along a predetermined path, such as a representative braiding device.

The present invention will now be further described by way of examples and comparative examples, but is not limited thereto.

Device

- Roblon Tornado 300 (TT83) is used to twist and fibrillate tapes into strands.

- Roblon Strander RS2-12-retractor (TT99) is used to wind a fibrillated tape on twelve carriers for Herzog equipment.

- Herzog SE 1 / 12-266 (TT57) is used for braiding strands containing fibrillated tape.

- Zwick 1474 Winding grip (Zwick 1474 Winding grip) / 800 kN Horizontal tensile tester Mensen Sbi. V. (800 kN horizontal tensile tester Mennens b.v.) is used to measure the tension of the braided rope.

matter

Ultra high molecular weight polyethylene tapes were prepared according to the process described in U.S. Patent No. 5,091,133. A tape having the following properties was obtained: Linear density: 43300 dtex; Toughness: 16.5 cN / dtex; Modulus: 1125 cN / dtex; Width: 100 mm; Area density: 42 g / m 2.

Production stage

The bobbin of the UHMWPE tape was mounted on a standard (non) winding frame (rolling takeoff).

The tape was twisted with strands of fibrillated tape using a Roblin Tornado 300 Twister. The twist level was chosen to be 18 tpm. 200 m long fibrillated tape Z-strand and 200 m long fibrillated tape S-strand were produced. For visual inspection, some of the fibrillated tape did not twist. A net-like coherent structure of filaments and fibrils could be observed for both strands of the fibrillated tape.

The fibrillated tape was cut into three pieces each having a length of 5 mm to measure the fibrillation range of the tape. The number of individual fragments within each path was counted. The Z-Strand had an average of 53 fragments, and the S-Strand had an average of 51 fragments. The fragments exhibited an irregular width distribution ranging from 0.1 to 5 mm. This irregular distribution was considered to be the repetition of the filaments of the fibrillated tape and the width of the fibrils.

A bobbin having Z-strand and S-strand of the fibrillated tape was mounted on a winding device of a Robon strander RS2-12. These devices were used to wind the strands onto a Herzog carrier. Finally, the carrier was mounted on a Herzog SE 1 / 12-266 (TT57) braiding machine and three ropes with different braiding cycles were produced.

Rope construction: 12 x 1 x 43300 dtex; Strand twist 18 tpm; Braiding pitch 64 mm, 70 mm and 76 mm. The rope diameter of all three ropes was 12 mm.

The test method referred to in this application is as follows:

The intrinsic viscosity (IV) is measured at 135 占 폚 in decalin according to ASTM-01601/2004 or alternatively by the method PTC-179 (Hercules Incorporated (PTC-179), Apr. 29, 1982) , The dissolution time being 16 hours, the amount of DBPC as antioxidant being 2 g / l solution, and the measured viscosity at different concentrations extrapolated to zero concentration.

The tensile properties of the tape were measured according to ISO 1184 (H). When calculating the modulus and strength, divide the measured tensile force by the linear density of the tape (dtex); Linear density is measured by weighing 10-meter long tapes in mg; The GPa value is calculated assuming a density of 0.97 g / cm3.

Claims (15)

Providing a uniaxially oriented tape comprising ultra high molecular weight polyethylene and having a tensile strength of at least 0.9 GPa as measured according to ISO 1184 (H); and
Simultaneously twisting and fibrillating the tape with twisted strands of fibrillated tape having a coherent network of filaments and fibrils,
Of the rope. The method according to claim 1,
Characterized in that the twist level of the twisted strands of the fibrillated tape is between 1 and 100 turns / meter (tpm). 3. The method according to claim 1 or 2,
Wherein the linear density of the tape is in the range of 400 to 200,000 dtex. 4. The method according to any one of claims 1 to 3,
Wherein the tape has an areal density in the range of 2 to 200 g / m < 2 >. 5. The method according to any one of claims 1 to 4,
Wherein the tape has a tensile strength of at least 1.2 GPa, preferably at least 1.5 GPa. 6. The method according to any one of claims 1 to 5,
Braiding, laying, twisting or bundling at least one of said twisted strands comprising a fibrillated tape. ≪ Desc / Clms Page number 13 > 7. The method according to any one of claims 1 to 6,
Wherein the uniaxially oriented tape is provided from a package. 8. The method of claim 7,
Characterized in that the unwinding is carried out by pulling off the tape from the fixed package upwards. A rope obtainable by a process according to any one of claims 1 to 8. 10. The method of claim 9,
A rope comprising at least one strand comprising a fibrillated tape having a tensile strength of at least 0.9 GPa as measured according to ISO 1184 (H) prior to fibrillation and comprising a coherent network of filaments and fibrils . 11. The method according to claim 9 or 10,
Characterized in that it comprises more than one strand comprising a fibrillated tape. 12. The method according to any one of claims 9 to 11,
Wherein the rope is a braided structure. The method according to any one of claims 9 to 12,
Wherein the at least one strand is a braid rope. An article comprising a rope according to any one of claims 9 to 13. 15. The method of claim 14,
Towing lines, lifting ropes, off-shore ropes, fishing lines, fishing nets, cargo net, mooring lines, towing lines, lifting ropes, A cargo curtain, a belt, a fabric, a raschel and a sling.

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