DE60308046T2 - METHOD FOR PRODUCING A MONOFILENT PRODUCT - Google Patents

Abstract

The invention relates to a process for making a monofilament-like product from a precursor containing at least one strand of a spun yarn made from polyolefin staple fibres, comprising the steps of a) exposing the precursor to a temperature within the melting point range of the polyolefin for a time sufficient to at least partly fuse adjacent fibres and b) simultaneously stretching the precursor at a draw ratio of at least 1.0. The invention further relates to a monofilament-like product obtainable by said process showing improved abrasion resistance, and to the use of said monofilament-like product for making various semi-finished and end-use products.

Description

The The invention relates to a process for producing a monofilament-type Products from a precursor, which contains at least one strand of polyolefin fibers, which the steps a) of exposing the precursor to a temperature within the melting point range of the polyolefin for a time sufficient is to at least partially fuse adjacent fibers, and b) simultaneously extending the precursor in a draw ratio of at least 1.0. The invention further relates to a monofilament-like Product which can be obtained by said method and the use of the monofilament-like product for manufacture various semi-finished and end-use products.

Such a method is from the EP 0 740 002 B1 known. This patent publication describes a method for producing a fishing line from yarns of filamentary materials, wherein a braided, twisted or twisted and folded fishing line of yarns of gel-spun polyolefin filaments is exposed to a temperature within the melting point range of the polyolefin for a time sufficient. to fuse at least partially adjacent filaments while simultaneously stretching the line in a draw ratio within a range of 1.01 to 2.5. The yarns applied in this process are continuous multi-filament yarns, especially those yarns by so-called gel spinning of polyethylene with a ultra-high molar mass polyethylene (UHMWPE) can be prepared, for example yarns commercially available under the name Spectra ^® or Dyneema ^®.

Fishing lines are generally monofilaments of synthetic polymers with a round solid structure that allows for convenient handling for ejection, spinning, and the lurching of baits. Such monofilament lines generally have a stiff texture and a smooth surface which together reduce mechanical resistance during ejection and allow longer spits while providing better release of fishing reels. Braided lines are less suitable for fishing lines because they tend to fringe at the end of the line, can trap water, provide an exterior surface susceptible to snagging and entanglement, and have an opaque white color that is too visible under water. That from the EP 0 740 002 B1 Known method also allows the production of monofilament-type fishing lines of braided or twisted lines of polyolefin multifilament yarns, wherein the lines are not associated with the said disadvantages of braided lines.

A disadvantage of in the EP 0 740 002 B1 described method is that the product thus obtained has a limited tear strength when exposed to abrasion conditions.

It is therefore an object of the present invention, a method for To provide a monofilament-like product, which does not show the mentioned disadvantage.

This The aim is according to the invention achieved with a process for producing a monofilament-like Products from a precursor, containing at least one strand of polyolefin fibers, comprising the steps a) of exposing the precursor to a temperature within the melting point range of the polyolefin for a time sufficient is to at least partially fuse adjacent fibers, and b) concurrently drawing the precursor in a draw ratio of at least 1.0, wherein the strand is a spun yarn of polyolefin staple fibers is.

With the method according to the invention For example, a monofilament-like product e.g. from a pledged or braided polyolefin yarn construction, wherein the product shows improved abrasion resistance, as reflected in the number of cycles to break expresses like in one of 'materials and Procedure 'described Test measured.

The by the method according to the invention obtained monofilament-like product also shows surprising a high tensile strength, which is much higher than the initial one Spun yarn or the folded yarn of such a spun yarn and as a precursor is used. The obtained monofilament-like product has continue to have a pleasant touch or feel and are easy to handle and knot; about that It also surprisingly shows a high knot strength and knot strength efficiency. Another Advantage of the method according to the invention is that the degree of merging can be easily varied and regulated can, making products with customized Property profiles are obtained. Yet another part is that the obtained monofilament-like product is effective with a Coating composition in an additional process step can be coated.

With the method according to the invention a monofilament-like product is prepared from a precursor, which contains at least one strand of polyolefin fibers. One Monofilament-like product is understood as a product that a look and feel which resemble more that of a monofilament than that of one Multifilamentgarns or a string or cord, but in the act is made of at least one strand, which is a Contains a large number of fibers, the fibers typically have a diameter of less than have about 50 microns. The monofilament-like product can have a Have diameters that vary within a wide range, e.g. from about 0.1 to 10 millimeters. A precursor is herein as an object of unlimited length to understand that contains at least one strand of polyolefin fibers, and is used as feed or starting material. A suitable one Precursor can in the form of, for example, a braided twine, a plied and twisted yarns, a twine or a dew, that's a bunch of strands but also in the form of a single-stranded yarn. One Strand of polyolefin fibers is understood as a fiber article such as a yarn that is predominantly, i. to 50 or more mass%, polyolefin fibers contains.

The Method according to the invention includes the step of exposing the precursor to a temperature within the melting point range of the polyolefin for a time sufficient is to fuse at least partially adjacent fibers. The conditions of this merging step are chosen so that the temperature and time of exposure are sufficient to Soften the polyolefin fibers and at least partially within the specific applied structure merge to let. The melting point range of the polyolefin is the temperature range between the peak melting point of a non-oriented polyolefin and the peak melting point a limited, highly oriented polyolefin fiber as determined by DSC analysis a scan rate of 20 ° C / min certainly. For UHMwPE fibers, the typically show a melting point range of 138-162 ° C, the temperature is preferably within the range of about 150 ° C to about 157 ° C. The residence times, while which of the precursors can be exposed to the melting temperature, within a wide Range, but are typically within the range from about 5 seconds to about 1500 seconds. Although higher temperatures rather reinforce the merger process, should pay attention Be careful not to apply too high a temperature as this is one Loss of strength of the product, which may be e.g. to a partial melting or other molecular relaxation effects leads.

During the Merger process changed look the look of the precursor from an initial one opaque white Color to a translucent, milky or even essentially transparent surface appearance of the product, depending on the degree of fusion and the nature of the precursor material. The light transmission of the product increases as the degree of fusion increases to the fibers too. Such an increase in translucency or translucency is a definite advantage for the application as underwater fishing lines.

For a monofilament-type It is sufficient for the product, which shows a slight final fraying, that the outer surface layer is at least partially fused by fibers, as by the Increase in light transmission you can see. A higher one Melting degree, e.g. also the binding of fibers in further inside located parts of a precursor or strand, however, is for the production of a product with a higher abrasion resistance and a higher one Bending stiffness, ie with more monofilament-like characteristics, prefers. The degree of fusion can be adjusted by varying the exposure temperature and / or exposure time set in the method according to the invention become.

The degree of fusion in the obtained product may be, for example, by visual inspection, for example, with the naked eye or by using a light or electron microscope; or by measuring mechanical properties such as strength or rigidity. Another possibility is to determine the amount and rate of absorption of a colored liquid, for example from a marker, as in EP 0 740 002 B1 described. The degree of fusion can also be derived from a test in which the loaded product is abraded over a metal rod and the number of movements is determined after which the monofilament-like product dissolves into its constituent filaments.

In a specific embodiment of the method, the degree of fusion is only very slight, or even barely measurable, in the product obtained. Surprisingly, it has been found that such a product, which has been stretched at elevated temperature, exhibits a significantly improved tensile strength over its precursor; let it be that the abrasion resistance is only slightly better. The invention therefore relates to a method of drawing a braided construction having at least one strand of spun yarn made of polyolefin staple fibers in a draw ratio of at least 1.1 with simultaneous exposure to a temperature within the melting point range of the polyolefin. The product obtained by this method shows improved tensile properties, but still has curvature properties that are very similar to the initial design.

The Method according to the invention includes also the simultaneous stretching of the precursor in a draw ratio, too draw ratio called, of at least 1.0. The application of a stretch ratio of at least 1 on the precursor while the exposure to heat prevents a decrease in the strength of the product. A stretch ratio of 1.1 or higher tends to improve especially the tensile strength. The Strength of the product then turns out to be surprising as essential higher than that of the precursor or the strands contained therein. About one certain draw ratio weakens this effect, or the strength may even decrease as one Consequence of partial damage or of tearing of fibers. Furthermore applies, the higher the stretch ratio, the lower the titer of the resulting product. The maximum draw ratio is thus of the type of the precursor and dependent on its fibers and is generally at most about 50. Preferably, the draw ratio is 1.1 to 40, 1.2 to 25, stronger preferably 1.3 to 10, or even 1.4 to 5.

Preferably the product obtained after step b) is cooled while it is kept under tension at the same time. This has the advantage that orientation in the resulting product during fusing and stretching at the fiber level and at the molecular level within the fibers are better maintained. Such a voltage results for example, from wrapping the product to packing afterwards to the previous steps of the method.

In the method according to the invention For example, at least one strand in the precursor is a spun yarn of polyolefin staple fibers That is, the spun yarn comprises at least 50% by mass of the polyolefin staple fibers. In general, you can Yarns of continuous filaments, staple fibers or combinations be made of it. Natural fibers fall into two categories Divide: short staple fibers (cotton-like, with a typical Pile or filament length from 15-60 mm) and long staple fibers (wool-like, typical staple length 40-200 mm). Synthetic fibers are first produced as continuous filaments; you can then go to Staple fibers either by cutting or stretch breaking method being transformed. Cutting generally leads to a uniform (square) Filament distribution (all filaments about the same length); nevertheless enable modified systems to maintain a certain variation in the Filament length. The stretch breaking leads generally staple fibers with a more Gaussian distribution of filament lengths. In In a stretch breaking process, the filaments are sandwiched between several Rows of rollers running at different speeds, until they break, stretched.

staple fibers can to yarn by a method of drawing and twisting strands of parallel fibers, commonly referred to as spiders become. For this reason, yarn made of staple fibers referred to as spun yarn.

industrial Close the yarn spinning process the following basic procedural steps: loosening, carding, Stretching and spinning. The release refers to separation and optionally cleaning e.g. from Bale pressed staple fibers. Carding is the other Solve and Separating fibers, for example by passing between rotating drums, covered with needles are. this leads to a thin one Orbit of partially parallel fibers, resulting in a dew-like Strand that often as a roving is formed. After that combing can be used to improve the orientation of fibers and small ones Remove fibers. during the For drawing, rovings are drawn out in one or more steps. Several rovings, either of the same or different Staple fibers, can be mixed together to obtain a uniform fiber density. The mixing of staple fibers in the carding stage can also be yarns produce mixtures of different natural and / or synthetic Fibers include. Before feeding to the spinning machine, the roving can be further stretched, while a slight twist or twist is added, called roving. While of spinning, the roving or roving is further pulled out and a twist is added to provide cohesion of the overlapping fibers, and the yarn is wound on spools or yarn carrier. Such a Pack of wound yarn can be of conical or cylindrical Form and is usually referred to simply as a pack.

The spinning process described leads to a twisted, single-strand yarn, also called single yarn or single yarn. Depending on the twisting direction used, such yarns are often referred to as either S or Z yarns. A twisted single-strand yarn is generally more 'jumpy', meaning that it tends to twist, tangle, skew, or bow to wrap when held under insufficient tension. In order to reduce this discontinuity, that is, to obtain a smooth or evened yarn that can be satisfactorily further processed into, for example, a textile fabric, it has generally been assumed in the industry that two or more strands of single yarns in an additional Step must be united. Such a union step is usually called doubling or twisting. For example, a twofold yarn or a double-layered yarn may be produced by twisting together two single-stranded Z yarns with S twisting or by twisting Z-type and S-type yarns together. The so obtained doubled yarns may also be stronger and more uniform than single-strand yarns.

The in the method according to the invention spun yarn used comprises at least 50% by mass polyolefin staple fibers. The Spun yarn can continue up to 50 mass% of one or more include other staple fibers, such as natural fibers or synthetic fibers Fibers to make a blended yarn. Suitable examples of such secondary Close staple fibers Wool, polyolefin, acrylic, polyester or polyamide, including aromatic Polyamide fibers, a.

In a special embodiment of the method according to the invention For example, the spun yarn comprises an amount of a staple yarn of a thermoplastic Polymer with a lower melting point range than the polyolefin staple fibers. The advantage of this is that an additional thermal bonding or sticking during of step a) can take place. The use of a spun yarn in the method according to the invention leave this possibility to, since the production of a mixed spun yarn easier and more economical than the production of a mixed multifilament yarn. examples for suitable thermoplastic polymers include copolymers of at least an α-olefin with other monomers, such as LLDPE, or ethylene-acrylic copolymers one. Effective amounts of such staple fibers can be determined by experiment are and are generally about 5 to 25% by mass.

In a further specific embodiment according to the invention, the main component of the spun yarn is not a polyolefin staple fiber but a staple fiber of a filament yarn of high strength and high modulus having a higher heat resistance than a polyolefin and which can not be thermally bonded per se, such as an aromatic one polyamide such as Kevlar ^® or Twaron ^®, a liquid crystal polyester yarn, or a yarn on polybenzoxazole or Polybenzothiazolbasis. Such spun yarn further comprises up to 50% by mass of a staple yarn of a thermoplastic polymer having a relatively low melting point range, for example, polyolefin staple fibers having a melting point below 200 ° C. Examples of suitable thermoplastic polymers include copolymers of at least one α-olefin with other monomers, such as LLDPE, or ethylene-acrylic copolymers. The advantage of this embodiment is that the thermal bonding can take place during step a), whereas without the presence of low melting point fibers, no monofilament-like product can be made from such high-strength and high-modulus filament yarns which have a high melting point has high heat resistance by exposure to heat while being stretched at the same time. Effective amounts of such thermoplastic heat fusible staple fibers can be determined by experimentation and are generally about 5 to 25 mass%. A monofilament-type spun yarn-based product comprising aromatic polyamide staple fibers and heat-fusible staple fibers produced by said process combines high strength, high abrasion resistance and high thermal resistance.

The Spun yarn and the staple fibers can continue the usual Additives, such as stabilizers, colorants, mineral particles, sizing agents and the like.

The Choice of other staple fibers, e.g. Type, length, titer (dpf), whether under the applied temperature and Time conditions can be melted together with the polyolefin staple fibers, and / or of additives, becomes mainly determined by the ultimate properties that are desired and Can by a person with experience using general Knowledge or routine experimentation.

Preferably For example, the spun yarn used in the method according to the invention comprises at least 60, 70, 80 or even 90% by mass polyolefin staple fibers because this is better mechanical Characteristics of the products obtained allows. For this reason, includes the applied spun yarn most preferably substantially only the staple fibers.

Staple fibers obtained from various polyolefin yarns may be selected as staple fibers for use in the process according to the invention. Particularly suitable polyolefin yarns are made from homopolymers and copolymers of ethylene or propylene. In addition, the polyolefins used may contain small amounts of one or more other monomers, particularly other alpha-olefins. Good results are achieved when linear polyethylene (PE) is chosen as the polyolefin. By linear polyethylene is meant polyethylene having less than one side chain per 100 carbon atoms, and preferably less than one side chain per 300 carbon atoms; a sidechain or branch, which usually contains at least 10 carbon atoms. The linear polyethylene may further contain up to 5 mole% of one or more comonomers, such as alkenes such as propylene, butene, pentene, 4-methylpentene or octene. In addition to the polyolefin, the fiber may contain small amounts of solvents or additives common to such fibers, such as antioxidants, spin finishes, heat stabilizers, colorants, etc.

Preferably, the polyolefin fiber, in particular the polyethylene fiber, has an intrinsic viscosity (IV) of more than 5 dl / g. Due to their long molecular chains, polyolefin fibers having such an IV have very good mechanical properties, such as high tear strength, modulus, and energy absorption upon cracking. This is also the reason why the polyolefin is even more preferably a polyethylene having an IV of more than 10 dl / g. The IV is determined according to the method PTC-179 (Hercules Inc. Rev. Apr. 29, 1982) at 135 ° C in decalin, the dissolution time is 16 hours, the antioxidant is DBPC in an amount of 2 g / L solution and the viscosity at various concentrations is extrapolated to zero concentration. Polyethylene with such a high viscosity is often called UHMwPE. UHMwPE filament yarn can be prepared by spinning a solution of UHMwPE into a gel fiber and stretching the fiber before, during and / or after partial or complete removal of the solvent, ie, by a so-called gel spinning method, such as in U.S. Pat EP 0 205 960 A in WO 01/73173 A1, in Advanced fiber spinning technology, ed. T. Nakajima, Woodhead Publ. (1994), ISBN 185573 182 7 and in references cited therein.

Preferably UHMwPE staple fibers are chosen, because they have a high strength with a relatively low density combine. In particular, the spun yarn comprising the process according to the invention is applied, UHMwPE staple fibers by a stretch breaking process from a multifilament UHMwPE yarn were produced because the broader fiber length distribution of such Stack leads to a yarn with better mechanical properties.

In a specific embodiment, the spun yarn used is a single-strand spun yarn. In another embodiment, the single-strand spun yarn as described in a co-pending application which has not yet been published is used in the process according to the invention. The single-strand spun yarn was made from at least 50 mass% staple fibers composed of a continuous polyolefin multifilament yarn having a tensile strength of at least 16 cN / dtex; a tensile modulus of at least 700 cN / dtex; and one denier per filament fiber of at most 18 dpf; while the staple fibers have an average fiber length between 40 and 180 mm, and show substantially no crimping or crimping; and the spun yarn has a twisting degree characterized by an α twisting coefficient of 40-100 t · m ^-1 · (m / g) ^-1/2 . Preferably, the staple fibers were obtained from highly oriented polyolefin fibers, such as those based on ultra high molecular weight polyethylene (UHMwPE). The advantage of this method is that translucent or semitransparent monofilament-like products having a relatively low titer, eg of 10-100, preferably 15-50 dTex, and a low specific gravity in a higher total production rate and lower total cost compared with that of of the EP 0 740 002 A1 known method, which emanates from multifilament yarns can be produced. The products obtained by this process are particularly suitable for medical applications, such as surgical sutures.

The α-twist coefficient characterizes the degree of twist of a yarn according to the Koechlin equation: T = α (Nm) ^1/2 , where T is the degree of twist expressed as the number of turns per meter (t · m ^-1 ), and Nm the metric yarn count or thickness (1000 / tex, or m / g). This rotation coefficient is also referred to as (metric) rotation factor or rotation multiplier; see, for example, "http://www.fibre2fashion.com/GLOSSARY/glossary17.htm". Preferably, the twist coefficient is between 60 and 100, 65 and 90, or even between 70 and 85.

This single-stranded spun yarn has a very low springiness and is quiet enough to allow further processing without first having to produce a doubled yarn. The staple fibers in the single-stranded spun yarn were obtained from a filament yarn having a linear density of at most 18 denier per filament (dpf), preferably at most 14, more preferably at most 10 dpf, and even more preferably at most 6 or at most 4 dpf. The lower the linear density of the Fa The spun yarn may be thinner, since a certain minimum number of fibers in a cross section is needed to give a yarn of sufficient integrity. In addition, a lower linear density of the fibers results in a higher tensile strength of the spun yarn at a constant yarn denier. In terms of fiber production efficiency, it is preferable that the linear density is at least 0.2, 0.3 or at least 0.5 dpf. Starting from thinner spun yarns has the advantage that thinner monofilament-like products can be made in a more economical way.

The in the method according to the invention applied single-stranded Spun yarn comprises polyolefin staple fibers which are essentially none ripple show, wherein the fibers are not, or only slightly, textured. The ripple is a measure of the ripple a fiber and can be considered the difference between the length of the fiber uncurled or completely stretched fiber and the curled Length to be expressed; this is the length the fiber, if this is essentially free of a restriction of Outside are. Essentially no ripples It indicates here that the length of the staple fibers in one unstressed condition at least 80% of the uncrunned Length makes up. Preferably, the curled length is at least 90% of the uncrimped Length, even better at least 95%. Essentially no ripples showing is further to be understood that no permanent rippling is included. For example, UHMwPE staple fibers can have a certain ripples show that maybe while the stacking introduced but this ripple is not permanent, as they are essentially at a suspension of the Fibers at expansion forces, the e.g. while of spiders can occur disappear.

In the method according to the invention At least one strand in the precursor is a spun yarn of polyolefin staple fibers. Of the precursor can also have one or more strands from other staple fibers and / or from continuous filaments included to become a monofilament-like product of different Merges between and within strands and with different mechanical properties and appearance and feel get. Such variations can by a person skilled in the art using general knowledge or from routine experiments. Preferably, all strands in the precursor Spun yarns based on polyolefin staple fibers, as this is the variation the degree of fusion and thus the product properties in one high dimensions allowed.

The Method according to the invention can with a precursor of different constructions, for example a braided one Construction, or a pleated and twisted construction, be performed. Preferably, a precursor applied with plied (or doubled) and twisted strands. This has the advantage that the precursor is easier and less expensive can be produced; and that the product obtained a better Power; especially surprising a good tear resistance during abrasion tests shows.

The Method according to the invention may further precede the step a) preconditioning of the precursor, or one or more strands in that, to bond the fibers together during the process Reinforce the merger step. Such a pretreatment step may include coating the precursor with a component or composition; cleaning the precursor, the means the washing of surface components like spin-finishes etc; or applying a high voltage plasma or a corona treatment.

In an embodiment becomes the precursor by application, e.g. by dipping or wetting with, one effective amount of a mineral oil (e.g., mineral oil from the degree of heat transfer with an average molar mass of about 250-700), of vegetable oil (e.g., coconut oil), or a preferably non-volatile one solvent for polyolefin, like paraffin, pretreated. This pretreatment step may be included Ambient conditions occur, or at an elevated temperature below the melting temperature range of the polyolefin fiber.

In another embodiment, the pretreatment comprises applying a coating composition to the precursor, which composition may be a solution or dispersion of a polymer that enhances bonding of the fibers to each other during exposure to a higher temperature in the fusing step, or otherwise improves performance , In a preferred embodiment, the precursor is coated with a polyurethane composition, such as a dispersion of film-forming polyurethane. Such a composition may further comprise components which help to improve the abrasion and cut resistance of the monofilament-like product. Examples of components improving the cut resistance are small single particles having high surface hardness such as mineral particles, ceramic particles, glass, metals and the like. The coating composition It may further comprise other additives such as colorants or stabilizers.

The Method according to the invention may further comprise a step in which a coating composition is applied to the product after steps a) and b) a coating layer to build. Such a coating composition may be a typical one Spinning finish include to easier handling and processing of the product in the following To facilitate operations; a compound or composition to provide adhesion during the subsequent production of composite articles comprising the product to regulate; or a binder composition containing the integrity and strength of the product further increased. Typical examples of the latter close binder compositions polyurethane or polyolefin-based, such as ethylene-acrylic copolymers, one. The coating composition may be in the form of a solution or Dispersion can be applied. Such a composition can further comprising components which further improve the abrasion or cut resistance improve the monofilament-like product. Examples of the components, which improve the cut resistance are small single particles with a high surface hardness, like various mineral or ceramic particles. The coating composition may further comprise other additives such as colorants, stabilizers, etc.

The Application of a coating composition in the process according to the invention is, as it turned out, relatively easy and effective in comparison with a process in which continuous filament yarn as precursor is applied. Obviously this is after the steps a) and b) product obtained more receptive across from such coatings, especially when the fibers on the surface of the Products were only partially fused.

The invention also relates to a monofilament-like product comprising an at least partially fused spun yarn of polyolefin staple fibers, which product can be obtained by the process according to the invention. This product has a unique structure and combines several beneficial properties; it has the translucent appearance of a monofilament, but its feel and feel are different from polyolefin monofilaments or monofilament-like products such as those described in U.S. Pat EP 0 740 002 B1 are known. The monofilament-like product according to the invention surprisingly shows a high tear resistance during the abrasion test; can be knotted easily, and the knotted product shows a high retention of strength. The monofilament-like product also surprisingly exhibits a high tensile strength, which is still substantially higher than the strength of the starting spun yarn in the precursor. Typically, the monofilament-like product has a tensile strength of at least 10 cN / dtex, preferably at least 15, 20 or even 25 cN / dTex. Such high strength is typically found for a precursor based product comprising a relatively high amount of UHMwPE staple fiber based spun yarn.

The by the method according to the invention available Monofilament-like product has a linear density, even titers called within wide limits, e.g. from 10 to 15,000 dTex, may vary. Generally, the product has a titer from 30 to 2500 dtex. The products with a lower titer are for use as seams and the like. With regard to applications such as fishing lines or protective clothing and clothing, the titre is preferably 100 until 1600 dTex, even stronger preferably 200 to 1200 dTex.

The The invention further relates to the use of a monofilament-type Product according to the invention for the manufacture of various semi-finished and end-use products, like fishing lines; seams Textiles; twine and ropes; composite yarns; and their use for example in cut-resistant objects.

The The invention also relates to semi-finished and end-use products which comprise the monofilament-like product according to the invention.

The The invention will now be further illustrated by the following examples and comparative experiments illustrated.

materials and procedures

Multifilament UHMwPE yarn, Dyneema ^® 1760SK60 (DSM High Performance Fibers, NL) having a titre of 1760 dTex, a tensile strength of 28 cN / dTex, a tensile modulus of 910 cN / dTex, and a denier per filament of fiber of about 1 dpf was a stretch breaking process is formed into staple fibers, such as for example play in the EP 0 445 872 A1 is described. The average length of the staple fibers was about 80 mm. The staple fibers were then spun into a single-strand yarn using a long staple type NSC equipment. The obtained yarn had a yarn count of about Nm44 (about 225 dtex), the degree of twist used corresponded to a coefficient of about 80 according to Koechlin's Law. The spun yarn showed little springiness as demonstrated by cutting a length of 100 cm, holding in a fixed vertical position at only one end and noticing a tendency to twist. Its tensile strength was about 15.0 cN / dTex, the tensile modulus was about 153 cN / dTex, and the elongation at break was about 4.3%. This material is referred to below as SSSY.

The Tensile strength (or strength) (and tensile modulus) with respect to multifilament and spun yarns, and monofilament-like products as in ASTM D885M specifies using a nominal gauge length of 500mm fiber Crosshead speed of 50% / min and Instron 2714 terminals defined and fixed. For the calculation of the strength will be the measured tensile forces divided the titer as by weighing 10 meters (or one other length) Fiber determined. Elongation is the measured elongation at break, expressed in% of the original Length after the clamping of the test copy.

The Knot strength is determined by measuring the strength of a test piece, which includes a Palomar node. The Palomar knot is a general purpose link that is suitable for connecting a fishing line recommended with a swivel, a snap connection or a hook becomes. The duplicate end of the test copy is through the eyelet of a Hakens guided and it becomes a simple overhand node made. The hook is then passed through the loop and the knot is tightened.

The Knot strength efficiency is measured as the relative value (%) of the Knot strength calculated to the measured tensile strength.

The abrasion resistance was prepared according to a procedure based on ASTM D 3108 tests described for determining the yarn friction. For this The purpose was the yarn friction measuring device, which is described in ASTM D 3108, adjusted so that an end the sample to be tested on an eccentric crank or a Camshaft, which is rotated by a motor, is attached, the other end is loaded with a weight. During the Tests, the sample is rubbed against a ceramic eyelet, and it will the number of cycles is determined until the sample fails (tears). The given number is the mean of at least 5 tests.

Comparative experiment A

When Precursor (hardening) material was a braided construction of a gel-spun multifilament UHMwPE yarn with a Titre of 224 dTex, a tensile strength of 39 cN / dTex, a tensile modulus of 1250 cN / dTex and one denier per filament fiber of about 1 dpf applied. This braid contained 8 strands of the middle one Firmness of braided yarn, expressed as weft or weft threads per centimeter, of 7.5 (expressed as 8x224 / 7.5; see Table 1).

These Braiding was done by a bath of liquid paraffin as a pretreatment step guided, and excess oil became Wiped off by this between fibers or nonwovens was performed. The paraffin content was calculated to be about 11 mass% by determination the mass increase after this step. The braid was then over first driven rollers in an oven at a constant temperature of 153.5 ° C was kept at a constant speed of 10 m / min guided. At the exit of the oven, the braiding became over second driven rolls guided. The speed of the second rollers was adjusted so that a stretch ratio of 1.9 and a stretch rate of 0.7 m / min. In the case, that a different stretch ratio to be applied, as in some other experiments the rate of stretching in the furnace kept approximately constant by varying the path length the sample in the oven and the speed of the second rolls. The oven is equipped with a series of rollers so that the sample path length in the Oven can be 2.8 to 58.8 meters.

The Product appearance changed from the beginning Opaque white too almost translucent; the surface it was still pretty smooth, though clearly less so smooth and shiny than the starting product. Also, the product felt rougher and stiffer and remained at a certain angle after the Curving.

The results of further tests are summarized in Table 1. It should be noted be that the determined knot strength efficiency is significantly lower than for similar products in the EP 0 740 002 B1 to report; this may be related to the type of node being used.

Comparative experiment B

The Experiment was mostly carried out analogously to Comparative Example A, it is that a twisted and fitted construction of 6 strands of the same multifilament yarn was formed, with a twist in the clockwise direction of 120 Turns / cm (indicated as 6/224; 120Z). The measured Paraffin content was about 12% by mass; the stretch ratio was 1.8. The results of the further tests are summarized in Table 1.

example 1

A braided construction, the 8 strands of the above SSSY material contained 12 rounds / cm (indicated as 8 x Nm44 / 12 in Table 1) was used as a precursor used. This braiding was analogous to Comparative Example A. sent through the oven, but without any pretreatment step and the use of a draw ratio of 1.0. The resulting Product had a similar appearance like its starting material; it was found that this a lower tensile strength than that originally used as strands Spun yarn owns. The product showed a high strength retention, after the knot has been formed.

Examples 2-3

The Example 1 was repeated, but now about 12% by mass paraffin added before step a), and it became a Strecker ratio of 1.8 and 1.7, respectively. The more translucent appearance of the products indicates that there is a greater fusion came. The surface grip was less smooth than for that Comparative Example A. Both resulting products have a higher one Tensile strength than that as strands Applied spun yarn, show a higher strength compared to one Bending or bending (stiffer) and maintain a certain angle after bending. The number of cycles to break during the abrasion test became with more than 5 times higher for the Example 2 as for Comparative Example A determined.

Examples 4-6

braided Constructions from the SSSY material described above, the 8 strands at 9.5 rounds / cm were used as precursors. Analogous to that Comparative Example A, this braid was passed through the oven, but without any pre-treatment step and the application of a stretch ratio from 1.0. The resulting product appeared to have a lower tensile strength to have that as strands applied spun yarn; but a knot could only have a high strength retention (Example 4). When applied to a draw ratio of 1.6 or 1.7 The tensile strength increased again as in the examples 2-3; however the abrasion resistance was only slightly better. Obviously, among the applied temperature and time conditions of the degree of fusion the fibers are not high enough to have a high abrasion resistance respectively without a pretreatment.

Examples 7-9

The Examples 4-6 were repeated, but now 13 mass% paraffin was added to the precursor. A strength increase vs. the original spun yarn was for all samples determine; Example 7 confirms the positive effects a higher one Melting degree on the abrasion resistance.

Examples 10-16

Braided constructions from the above-described material containing 8 strands at 7.5 picks / cm were used as precursors. Example 10 demonstrated that at a draw ratio of 1.0, no increase in tensile strength is observed; and that there is little fusion without pretreatment and under the chosen conditions. The addition of paraffin and the increase in the exposure temperature increase the degree of fusion, as assessed by the change in appearance. Improved fusion was also evident from the product's resistance to dissolution resistance when rubbed over a metal rod; Ex 11 was able to withstand 18, Ex 12 and 13 about 33 movements. A 4-5-fold increase was noted in the number of cycles until they in the abrasion resistance test. A higher temperature or stretch ratio did not result in further improvement in tensile properties for the present precursor construction.

Example 17

The stranded Spun Yarn SSSY was considered a precursor used. The pretreatment consisted in the application of an aqueous Polyurethane dispersion, L9010 from GOVI (BE) by immersion. Of the Polyurethane content was (in the resulting product) with about 15 mass% determined. The combination of pretreatment, suspension of heat and stretching with a draw ratio of 1.6 increased the Tensile strength of the product clearly. The product also had one higher Stiffness, a more translucent look, and it could easily a knot with a high strength retention can be formed.

Examples 18-22

When precursor was a 6-fold yarn based on SSSY with a twist in the Clockwise of 120 turns / cm (indicated as 6 / Nm44; 120Z) applied. In Example 19, about 13.5 mass% paraffin was used as a pretreatment added, combined with a draw ratio of 1.8. This fused product showed a very good tear resistance while of the abrasion test, about 15-fold increase vs. Comparative example B. Those with a polyurethane pretreatment prepared samples (Ex 20-22; PUR content approx 16 mass%) showed very good tensile properties and knot strength (Efficiency) and improved abrasion resistance.

Examples 23-24

The Products were based on an 18-fold twisted yarn (the starting strands were SSSY) with about 12.5 mass% paraffin and were among similar Conditions as previously prepared. The obtained for these thicker products Results with titers of about 4100 and 2500 dTex agree with the other results.

Claims (11)

A process for producing a monofilament-like product from a precursor comprising at least one strand of polyolefin fibers, comprising the steps of a) exposing the precursor to a temperature within the melting point range of the polyolefin for a time sufficient to at least partially fuse adjacent fibers, and b) simultaneously extending the precursor in a draw ratio of at least 1.0, characterized in that the strand is a spun yarn of polyolefin staple fibers. The method of claim 1, wherein the draw ratio is 1.2 to 25 is. A method according to any one of claims 1-2, wherein the polyolefin is a polyethylene with an extremely high molar mass is. A method according to any one of claims 1-3, wherein the staple fibers by stretch breaking a polyolefin multifilament yarn were obtained. A method according to any one of claims 1-4, wherein the precursor folded and twisted strands contains. The method of any one of claims 1-5, further comprising a pretreatment step preceding step a) from the precursor, to improve the connection of the fibers with each other. The method of claim 6, wherein the pretreatment the application of an oil at the precursor includes. The method of claim 6, wherein the pretreatment applying a polyurethane composition to the precursor. The method of any one of claims 1-8, further comprising a step for applying a coating composition for the product after steps a) and b). Monofilament-like product comprising at least one partially fused spun yarn of polyolefin staple fibers, available by the method according to at least one of claims 1-9. Use of the monofilament-like product according to Claim 10 for the manufacture of various semi-finished and end-use products, like fishing lines or cut-resistant objects.