Ultra-high molecular weight polyethylene fusion yarn and its manufacturing method

Abstract

Provided are ultra-high molecular weight polyethylene multifilaments and ultra-high molecular weight polyethylene containing liquid paraffin having an average molecular weight of at least 400. The fused yarn has a liquid paraffin content of more than 0% by weight and not more than 13% by weight based on the entire yarn, of which the liquid paraffin content present on the yarn surface is more than 0% by weight and not more than 10% by weight.

Description

[Technical field]

[0001] The present invention relates to a fusion yarn in which a plurality of ultra-high molecular weight polyethylene filaments are fused together, and a method for producing the same. [Background technology]

[0002] 2. Description of the Related Art Known threads used for marine materials such as fishing lines and fishing nets, ropes, racket strings, and the like include monofilament threads and multifilament threads made up of a plurality of monofilaments. For example, monofilament threads have excellent surface smoothness and low friction resistance. Therefore, when monofilament threads are used as fishing lines, they can be cast far away. Furthermore, monofilament threads do not trap water inside, so they also drain well. However, since monofilament threads are generally highly rigid, the thicker they are, the less flexible they become, making them difficult to use as fishing lines. Among them, ultra-high molecular weight polyethylene filaments are high in strength, but are difficult to manufacture in proportion to their thickness, and have the problem of being difficult to handle due to their high rigidity.

[0003] On the other hand, by appropriately setting the number and thickness of monofilaments, multifilament yarn can be made into a yarn of a desired thickness and excellent flexibility. Therefore, multifilament yarn is easy to handle and can be suitably used, for example, as a fishing line. In particular, ultra-high molecular weight polyethylene multifilament yarn has the advantage of being easy to handle while being high strength. However, ultra-high molecular weight polyethylene multifilament yarn has the problem of poor drainage because it is prone to trapping water inside. Furthermore, ultra-high molecular weight polyethylene multifilament yarn has the problem that the filaments at the cut parts may break apart and become fuzzy. Note that "breaking apart" refers to something that was once bundled together breaking into several pieces. A multifilament yarn having a single thread-like form, such as a monofilament yarn, has good water drainage and can suppress the filaments from coming apart. Hereinafter, a single thread-like form, such as a monofilament yarn, will be referred to as "monofilament-like."

[0004] The present applicant has previously proposed an ultra-high molecular weight polyethylene fused yarn in which the individual filaments are sufficiently fused, which contains 15% by weight or more of liquid paraffin having an average molecular weight of 400 or more (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6862031 Summary of the Invention

[0006] The ultra-high molecular weight polyethylene fusion yarn is used, for example, as a fishing line, etc. Since the fishing line comes into contact with reels, rod guides, etc., the ultra-high molecular weight polyethylene fusion yarn is required to have not only excellent fusion properties but also a low dynamic friction coefficient. [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a fusible ultra-high molecular weight polyethylene yarn having excellent fusibility and a low dynamic friction coefficient. [Means for solving the problem]

[0008] In one aspect of the present invention, an ultra-high molecular weight polyethylene fusion yarn can be provided. The first example of ultra-high molecular weight polyethylene fusion yarn is Multiple polyethylene monofilaments are fused together A fusion yarn comprising ultra-high molecular weight polyethylene multifilaments and liquid paraffin having an average molecular weight of 400 or more, The liquid paraffin is not present inside the polyethylene monofilament, The content of the liquid paraffin is more than 0% by weight and 8% by weight or less with respect to the entire yarn, threadThe content of liquid paraffin on the surface is For the whole thread More than 0% by weight and not more than 6% by weight.

[0010] The ultra-high molecular weight polyethylene fused yarn of the second example is the ultra-high molecular weight polyethylene fused yarn of the first example, wherein the content of the liquid paraffin is more than 0% by weight and not more than 5% by weight with respect to the entire yarn, and the content of the liquid paraffin present on the yarn surface is For the whole thread More than 0% by weight and not more than 2% by weight.

[0011] Example 3 The ultra-high molecular weight polyethylene fusion yarn is the first example Or in the second example In the ultra-high molecular weight polyethylene fusible yarn, the fusible yarn has a fineness of 10 dtex or more and 500 dtex or less.

[0012] In another aspect of the present invention, a method for producing ultra-high molecular weight polyethylene fusion yarn can be provided. A method for producing ultra-high molecular weight polyethylene fusion yarn, comprising: an ultra-high molecular weight polyethylene multifilament; and liquid paraffin having an average molecular weight of 400 or more, the content of the liquid paraffin being greater than 0% by weight and less than 13% by weight based on the total weight of the yarn; thread The content of liquid paraffin on the surface is For the whole thread A method for producing an ultra-high molecular weight polyethylene fused yarn having a paraffin content of more than 0% by weight and not more than 10% by weight, comprising the steps of: impregnating an ultra-high molecular weight polyethylene multifilament with liquid paraffin having an average molecular weight of 400 or more; obtaining a fused yarn precursor by heating and drawing the ultra-high molecular weight polyethylene multifilament containing the liquid paraffin; and removing the liquid paraffin present on the surface of the fused yarn precursor by contacting the fused yarn precursor with a removal liquid. Effect of the Invention

[0013] The ultra-high molecular weight polyethylene fused yarn of the present invention has excellent fusibility and is therefore unlikely to separate into individual filaments. Such ultra-high molecular weight polyethylene fused yarn has a monofilament-like structure and is easy to drain. Furthermore, the ultra-high molecular weight polyethylene fusion yarn of the present invention has a low dynamic friction coefficient and can be suitably used, for example, as a fishing line. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a front view showing one form of an ultra-high molecular weight polyethylene multifilament. [Diagram 2] FIG. 13 is a front view showing another form of ultra-high molecular weight polyethylene multifilament. [Diagram 3] FIG. 13 is a front view showing another form of ultra-high molecular weight polyethylene multifilament. [Figure 4] FIG. 1 is a reference diagram showing one form of an apparatus for manufacturing ultra-high molecular weight polyethylene fusion yarn. [Diagram 5] A reference diagram showing the system of the impregnation device and excess removal device. [Figure 6] FIG. 1 is a reference diagram showing another embodiment of an apparatus for manufacturing ultra-high molecular weight polyethylene fusion yarn. [Figure 7] The same reference diagram. [Figure 8] Front view of ultra-high molecular weight polyethylene fusion yarn. [Figure 9] FIG. 9 is an enlarged cross-sectional view taken along line IX-IX in FIG. 8 . [Figure 10] FIG. 1 is an explanatory diagram of a method for evaluating thread stickiness. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will now be described with reference to the accompanying drawings. In this specification, when multiple numerical ranges expressed as being equal to or greater than a lower limit and equal to or less than an upper limit are separately described, any lower limit and any upper limit can be selected to set a numerical range of "equal to or greater than any lower limit and equal to or less than any upper limit."

[0016] [Outline of ultra-high molecular weight polyethylene fusion yarn] The ultra-high molecular weight polyethylene fused yarn of the present invention comprises an ultra-high molecular weight polyethylene multifilament and liquid paraffin, and the ultra-high molecular weight polyethylene multifilament is fused. The ultra-high molecular weight polyethylene fused yarn has a liquid paraffin content of more than 0% by weight and not more than 13% by weight based on the entire yarn, and the liquid paraffin content on the yarn surface is more than 0% by weight and not more than 10% by weight. The ultra-high molecular weight polyethylene fused yarn has excellent fusibility and thus has a monofilament-like structure, and further has the advantage of a low dynamic friction coefficient. Here, "ultra-high molecular weight polyethylene fused yarn" refers to a yarn obtained by fusing each ultra-high molecular weight polyethylene monofilament that constitutes an ultra-high molecular weight polyethylene multifilament. "Ultra-high molecular weight polyethylene multifilament" refers to the state before each monofilament is fused, and "ultra-high molecular weight polyethylene monofilament" refers to the ultra-high molecular weight polyethylene long fiber that constitutes an ultra-high molecular weight polyethylene multifilament. Hereinafter, "ultra-high molecular weight polyethylene" will be referred to as "UHPE."

[0017] [UHPE multifilament (UHPE multifilament before fusion)] The UHPE multifilament is composed of multiple UHPE monofilaments. UHPE is polyethylene with an increased molecular weight, for example, polyethylene with a molecular weight of 400,000 or more, preferably polyethylene with a molecular weight of 600,000 or more. The UHPE has a melting point of 140° C. or more. The UHPE monofilament is a filament produced by so-called gel spinning of UHPE. The tensile strength of the UHPE multifilament is 19.6 cN / dtex or more, preferably 24.5 cN / dtex or more and 49.0 cN / dtex or less, more preferably 29.4 cN / dtex or more and 39.2 cN / dtex or less. For example, a commercially available product can be used as such a high-strength UHPE multifilament. Examples of commercially available products include "Dyneema" manufactured by DSM, "Spectra" manufactured by Honeywell, and "Izanas" manufactured by Toyobo. The tensile strength can be measured in accordance with JIS L 1013 (2010)-8.5.

[0018] The fineness of the UHPE monofilament is not particularly limited. If the fineness of the UHPE monofilament is too small, the gap between adjacent monofilaments in the multifilament becomes relatively small, making it difficult for liquid paraffin to uniformly impregnate the inside of the multifilament, and there is a risk of the fusion property being reduced. From this viewpoint, the fineness of the UHPE monofilament is, for example, 0.5 dtex or more, preferably 1.0 dtex or more. On the other hand, if the fineness of the UHPE monofilament is too large, the gap between adjacent monofilaments in the multifilament becomes relatively large, and there is a risk of the number of joining points (fusion) between filaments per unit volume being reduced. From this viewpoint, the fineness of the UHPE monofilament is, for example, 5.0 dtex or less, preferably 4.0 dtex or less. In this specification, the unit of fineness (thickness) "tex" is the weight (in grams) per 1000 m, and the unit of fineness (thickness) "dtex" is the weight (in grams) per 10000 m. In the present invention, the fineness can be measured in accordance with JIS L 1013 (2010)-8.3.1-b)B method.

[0019] The UHPE multifilament is composed of a plurality of the UHPE monofilaments. The number of UHPE monofilaments constituting the UHPE multifilament is not particularly limited, and is, for example, 5 to 5000, preferably 10 to 2500. The fineness of the UHPE multifilament is generally calculated by multiplying the fineness of the UHPE monofilament by the number of UHPE monofilaments. The UHPE multifilament may be in the form of a plurality of UHPE monofilaments that constitute it, which are simply drawn together, or in the form of a plurality of UHPE monofilaments that are drawn together and twisted, or in the form of a braided cord made of a plurality of UHPE monofilaments. The twist may be either an S twist (right twist) or a Z twist (left twist). Examples of the braided cord include a form in which a plurality of filaments are alternately braided, and a form in which a plurality of filaments are braided around a filament that serves as a core material. The filaments used for the braided cord may be twisted in advance. FIG. 1 shows a UHPE multifilament 21 made of a plurality of aligned UHPE monofilaments 3, FIG. 2 shows a UHPE multifilament 22 made of a plurality of aligned UHPE monofilaments 3 twisted in an S-twist, and FIG. 3 shows a UHPE multifilament 23 made of a plurality of aligned UHPE monofilaments 3 twisted in a Z-twist.

[0020] When the UHPE multifilament is twisted, its twist coefficient K1 is not particularly limited, but is preferably more than 0 and not more than 5500, more preferably 1000 or more and 5000 or less, and even more preferably 2000 or more and 4500 or less. By using a UHPE multifilament having a twist coefficient K1 in the above range, a UHPE fusion yarn having a knot strength ratio a / b in the range of 0.9 or more and 1.1 or less can be obtained. Note that a UHPE multifilament in the form of a plurality of UHPE monofilaments simply pulled together has a twist coefficient K1 of zero. The twist factor K1 of UHPE multifilament is calculated by the formula 1: K1 = t × D 1 / 2 Here, t in the above formula 1 represents the number of twists (turns / m) of the UHPE multifilament, and D in the above formula 1 represents the fineness (tex) of the UHPE multifilament.

[0021] [Liquid paraffin] Liquid paraffin is a colorless liquid paraffin under standard conditions (23°C, 1 atm, 50% RH). Liquid paraffin is a collection of alkanes mainly having 20 or more carbon atoms. Mineral oil is a general term for a mixture of hydrocarbon compounds and impurities derived from underground resources such as petroleum, natural gas, and coal. Liquid paraffin differs from mineral oil in that it is made by refining alkanes with 20 or more carbon atoms. In the present invention, liquid paraffin having an average molecular weight of 400 or more is used, preferably liquid paraffin having an average molecular weight of 420 or more is used, more preferably liquid paraffin having an average molecular weight of 430 or more is used, and even more preferably liquid paraffin having an average molecular weight of 450 or more is used. By containing a predetermined amount of such liquid paraffin inside the yarn and on the yarn surface, a UHPE fused yarn having excellent fusibility and a low dynamic friction coefficient can be obtained. There is no particular upper limit for the average molecular weight of liquid paraffin, but if it is too large, the fluidity decreases and it may become difficult for the liquid paraffin to be evenly impregnated into the inside of the multifilament (the gaps between each monofilament). From this viewpoint, the upper limit for the average molecular weight of liquid paraffin is 800 or less, preferably 700 or less, more preferably 600 or less, and even more preferably 490 or less. For example, a commercially available product can be used as the liquid paraffin. An example of a commercially available product is "Moresco White" by MORESCO Co., Ltd. Here, the average molecular weight of liquid paraffin can be calculated in terms of normal paraffin from a calibration curve obtained by gas chromatography using normal paraffin as a standard substance. A specific method for measuring the average molecular weight of liquid paraffin is as described in the following Examples.

[0022] [UHPE fusion yarn manufacturing method] The method for manufacturing the UHPE fused yarn of the present invention includes, for example, a step of impregnating a UHPE multifilament with a liquid paraffin having an average molecular weight of 400 or more (impregnation step), a step of obtaining a fused yarn precursor by heating and stretching the UHPE multifilament containing the liquid paraffin (fusion step), and a step of removing the liquid paraffin present on the surface of the fused yarn precursor (removal step). In the removal step, the liquid paraffin present on the surface of the fused yarn precursor is not completely removed (the liquid paraffin on the surface is made zero), but is an incomplete removal. That is, the removal step is a step of partially removing the liquid paraffin on the surface of the fused yarn precursor. Here, the "fused yarn precursor" means a UHPE fused yarn in a state where a relatively large amount of liquid paraffin remains on the surface.

[0023] FIG. 4 is a reference diagram showing an example of a manufacturing apparatus 8 for UHPE fused yarn. The manufacturing apparatus 8 has a zone Z1 for obtaining a fused yarn precursor 5b (a UHPE fused yarn in a state where a relatively large amount of liquid paraffin remains on the surface) and a zone Z2 for actively removing the liquid paraffin on the surface of the fused yarn precursor 5b. The arrows in FIG. 4 indicate the traveling direction of the UHPE multifilament 5a and the like (the same applies to FIG. 5).

[0024] <Zone for fusing UHPE multifilaments to produce a fused yarn precursor> The UHPE multifilament 5a, which is the raw yarn, is loaded into the yarn unwinding device 61. As described above, the twisted UHPE multifilament 5a may be loaded, or the untwisted UHPE multifilament 5a may be loaded. The UHPE multifilament 5a may be twisted between the yarn unwinding device 61 and the first drawing device 62. The UHPE multifilament 5a unwound from the yarn unwinding device 61 is drawn while being sent from the first drawing device 62 to the second drawing device 66. As the first and second drawing devices 62 and 66, for example, a drawing device consisting of a plurality of rollers can be used. Between the first drawing device 62 and the second drawing device 66, an impregnation device 63, an excess removal device 64, and a heating device 65 are arranged in this order. The impregnation device 63 impregnates the UHPE multifilament 5a with liquid paraffin. The method of impregnating the liquid paraffin is not particularly limited, and examples thereof include applying the liquid paraffin to the UHPE multifilament 5a using a nonwoven fabric, a woven fabric, a brush, or a sponge, passing the UHPE multifilament 5a in a bath containing liquid paraffin (dipping), and spraying the liquid paraffin onto the UHPE multifilament 5a using a spray or the like. The excess removal device 64 removes excess liquid paraffin from the UHPE multifilament 5a after impregnation with the liquid paraffin. The removal method is not particularly limited, and examples thereof include wiping off the liquid paraffin using a dry nonwoven fabric or woven fabric, and removing the liquid paraffin from the surface of the UHPE multifilament 5a using a roller or the like. The heating device 65 applies heat to the UHPE multifilament 5a after impregnation with the liquid paraffin. The heating device 65 is not particularly limited, and examples thereof include an oven.

[0025] FIG. 5 is a reference diagram showing an example of the impregnation device 63 and the surplus removal device 64. 5, the impregnation device 63 has a supply unit 631 that supplies liquid paraffin, a storage unit 632 that stores the liquid paraffin supplied from the supply unit 631, and an impregnation unit 633 that impregnates the UHPE multifilament 5a with the liquid paraffin stored in the storage unit 632. Note that countless dots are applied to the portion where the liquid paraffin exists. Liquid paraffin is supplied from the supply unit 631 to the storage unit 632 so that the liquid level of the liquid paraffin in the storage unit 632 is maintained at a predetermined height. A cloth-like body that can be impregnated with liquid paraffin is used as the impregnation unit 633. Examples of the cloth-like body include nonwoven fabric, felt, and a composite material of nonwoven fabric and felt that can be impregnated with liquid paraffin. One part (e.g., a lower part) of the cloth-like body is immersed in the liquid paraffin in the storage unit 632, and the opposite part (e.g., an upper part) of the cloth-like body is in contact with the UHPE multifilament 5a. The liquid paraffin in the storage unit 632 flows along the cloth-like body that is the impregnation unit 633, comes into contact with the UHPE multifilament 5a, and is impregnated therein. The impregnation section 633 is configured to appropriately set the distance from the liquid level of the storage section 632 to the UHPE multifilament 5a, the contact area and contact pressure (contact strength) of the UHPE multifilament 5a with the cloth-like body, etc. By setting the above items of the impregnation section 633, the amount of liquid paraffin impregnated into the UHPE multifilament 5a can be adjusted.

[0026] The excess removal device 64 is disposed downstream of the impregnation section 633. A cloth-like material capable of absorbing liquid paraffin is used as the excess removal device 64. Examples of the cloth-like material include nonwoven fabric, felt, or a composite material of nonwoven fabric and felt capable of absorbing liquid paraffin. By wrapping such a cloth-like material around the UHPE multifilament 5a, the excess liquid paraffin on the UHPE multifilament 5a can be removed. The excess removal device 64 is configured so that the contact area and contact pressure (contact strength) of the cloth-like material with the UHPE multifilament 5a can be appropriately set. By setting the above items of the excess removal device 64, the amount of excess liquid paraffin removed from the UHPE multifilament 5a can be adjusted.

[0027] The UHPE multifilament 5a drawn out from the yarn unwinding device 61 is impregnated with liquid paraffin having an average molecular weight of 400 or more by the impregnation device 63 and the excess removal device 64, and the excess is removed. The amount of liquid paraffin contained in the UHPE fused yarn, which is the final product, can be set by appropriately adjusting the amount of liquid paraffin impregnated into the UHPE multifilament 5a and the amount of liquid paraffin removed. The UHPE multifilament 5a impregnated with liquid paraffin is heated by the heating device 65. It is preferable to heat the UHPE multifilament 5a so that the temperature of the UHPE multifilament 5a is in the range of 140°C to 158°C. After heating, the UHPE multifilament 5a is stretched in the longitudinal direction by the second stretching device 66 to obtain the fused yarn precursor 5b. The circumferential speed of the rollers of the second stretching device 66 is made faster than the circumferential speed of the rollers of the first stretching device 62, so that the UHPE multifilament 5a can be appropriately stretched. The stretching ratio is preferably in the range of 1.5 to 2.5 times in order to maintain or increase the orientation of the molecular chains of the UHPE. In the illustrated example, a one-stage heating and stretching device is exemplified, but the number of stretching stages, the number and length of heating devices, etc. can be changed as appropriate.

[0028] <Zone for removing liquid paraffin from the surface of the fused yarn precursor to produce UHPE fused yarn> A predetermined amount of liquid paraffin present on the surface of the fusion-thread precursor 5b is removed. The liquid paraffin present on the surface of the fusion-thread precursor 5b can be easily removed, for example, by contacting the fusion-thread precursor 5b with a removal liquid. Representative examples of the removal liquid include organic solvents. The type of the organic solvent is not particularly limited as long as it can dissolve liquid paraffin, and examples of the organic solvent include alcohols, ketones, ethers, esters, aliphatic and aromatic hydrocarbons, halogenated hydrocarbons, amides, and cellosolves. Specifically, examples of the organic solvent include n-butanol, 2-butanol, cyclohexanol, isopropyl alcohol, t-butyl alcohol, glycerin, ethylene glycol, acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 2-hexanone, diethyl ether, tetrahydrofuran, dioxane, anisole, ethyl acetate, butyl acetate, methyl lactate, n-hexane, benzene, toluene, xylene, chloroform, dichloromethane, dichloroethane, dimethylformaldehyde, dimethylacetamide, methyl cellosolve, and ethyl cellosolve. These solvents can be used alone or in combination of two or more.

[0029] For example, the fusion-thread precursor 5b is passed through a bath 71 that contains a removal liquid such as an organic solvent. The removal liquid in the bath 71 in FIG. 4 is marked with numerous large dots. The fusion-thread precursor 5b is sent through the bath while being in contact with the removal liquid, so that the liquid paraffin on the surface of the fusion-thread precursor 5b can be removed. The amount of liquid paraffin removed from the surface of the fusion-thread precursor 5b can be set by adjusting the type of removal liquid, the time for which the fusion-thread precursor is in contact with the removal liquid, and the like. If necessary, the bath 71 may be equipped with a brush, an ultrasonic generator, or the like. By tracing the surface of the fusion-thread precursor 5b with a brush or adding ultrasonic waves to the removal liquid in the bath 71, the effect of removing the liquid paraffin on the surface of the fusion-thread precursor 5b is enhanced. By removing the UHPE fused yarn 5c from the bath 71, the amount of liquid paraffin on the yarn surface is adjusted to a predetermined amount. After being removed from the bath 71, the UHPE fused yarn 5c may be dried as necessary. The drying device 72 is not particularly limited, and examples thereof include a heating device such as an oven, and a blower that blows hot air or room temperature air. The obtained fused UHPE yarn 5c is wound up by a yarn winding device 67.

[0030] <Modification> The manufacturing apparatus 8 shown in Figure 4 illustrates a case in which the processes from fusing the UHPE multifilaments 5a to removing the liquid paraffin from the surface of the fused yarn precursor 5b are performed in a single line, but this is not limited to this and the processes may be performed separately in two or more lines. For example, as shown in Fig. 6 and Fig. 7, the manufacturing apparatus 8 has a first line 81 for producing a fused yarn precursor 5b by fusing UHPE multifilaments 5a, and a second line 82 for producing a UHPE fused yarn 5c by removing liquid paraffin from the surface of the fused yarn precursor 5b. The first line 81 and the second line 82 are independent. The operation of the manufacturing apparatus 8 having the first line 81 and the second line 82 is basically the same as that of the apparatus 8 shown in Fig. 4. Briefly, as shown in FIG. 6, the raw yarn UHPE multifilament 5a is unwound from a yarn unwinding device 61, and is drawn while being sent from a first drawing device 62 to a second drawing device 66. Furthermore, between the first drawing device 62 and the second drawing device 66, the UHPE multifilament 5a is impregnated with liquid paraffin by an impregnation device 63, and the excess liquid paraffin is removed by an excess removal device 64. The obtained fusion yarn precursor 5b is wound up by a yarn winding device 68. Next, as shown in FIG. 7, the fusion yarn precursor 5b is unwound from a yarn unwinding device 69, and the fusion yarn precursor 5b is immersed in a bath 71 containing a removal liquid, and then dried by a drying device 72 as necessary. The obtained UHPE fusion yarn 5c is wound up by a yarn winding device 67.

[0031] [UHPE fusion yarn] The UHPE fusion yarn contains the above-mentioned UHPE multifilament and the above-mentioned liquid paraffin having an average molecular weight of 400 or more. In the UHPE fused yarn, the liquid paraffin content is more than 0% by weight and not more than 13% by weight based on the entire yarn. The liquid paraffin content refers to the content of all liquid paraffin contained in the UHPE fused yarn when the UHPE fused yarn is taken as 100% by weight. Hereinafter, this liquid paraffin content may be referred to as the "total content." The total liquid paraffin content is preferably more than 0% by weight and not more than 8% by weight, more preferably 0.5% by weight or more and 5% by weight or less, and even more preferably 1.0% by weight or more and 5% by weight or less.

[0032] Furthermore, in the UHPE fused yarn, the content of liquid paraffin present on the yarn surface is more than 0% by weight and not more than 10% by weight. Hereinafter, this liquid paraffin content may be referred to as "surface content." The surface content of liquid paraffin is preferably more than 0% by weight and not more than 6% by weight, more preferably 0.1% by weight or more and 5% by weight or less, and even more preferably 0.1% by weight or more and 2% by weight or less. In addition, in the UHPE fused yarn, the content of liquid paraffin present inside the yarn is preferably 0.1% by weight to 6% by weight, more preferably 0.3% by weight to 5% by weight, and even more preferably 0.4% by weight to 4% by weight. Hereinafter, this liquid paraffin content may be referred to as the "internal content."

[0033] Here, the total liquid paraffin content (the content of all liquid paraffin relative to the entire yarn) can be calculated by the formula: Total content (wt%) = X / M x 100. X represents the weight of all liquid paraffin contained in the UHPE fused yarn per unit length, and M represents the weight of the UHPE fused yarn per unit length containing liquid paraffin. The weight of all liquid paraffin contained in the UHPE fused yarn per unit length can be measured by component analysis of the UHPE fused yarn. The total content of liquid paraffin may also be determined by a simple measurement method. For example, the total content of liquid paraffin can be determined by the formula: total content (wt%) = (MN) / M x 100. The M represents the weight per unit length of the UHPE fused yarn containing liquid paraffin, and the N represents the weight per unit length of the UHPE fused yarn obtained by heat drawing treatment without impregnating with liquid paraffin (UHPE fused yarn not containing liquid paraffin).

[0034] The surface content of liquid paraffin can be calculated by the formula: Surface content (wt%) = (MV) / M x 100. The M represents the weight per unit length of the UHPE fusion yarn containing liquid paraffin, and the V represents the weight of the UHPE fusion yarn after removing the liquid paraffin present on the surface of the unit length of the UHPE fusion yarn. For example, the V can be obtained by immersing a unit length of the UHPE fusion yarn in isopropyl alcohol for a predetermined time and drying the UHPE fusion yarn, and then measuring the weight of the UHPE fusion yarn. The specific methods for measuring the total content and surface content of liquid paraffin are as described in the Examples below. The internal content of liquid paraffin is calculated by subtracting the surface content from the total content.

[0035] Fig. 8 is a front view of the UHPE fusion yarn 5c with both ends omitted, and Fig. 9 is a cross-sectional view thereof. Note that Fig. 9 is a reference view that shows a schematic cross section of the yarn. As shown in Fig. 9, UHPE fusion yarn 5c is formed by fusion of a plurality of UHPE monofilaments X, and is formed like a monofilament. The UHPE monofilaments X are shaded. Note that although Fig. 9 clearly shows the interface (boundary) between adjacent UHPE monofilaments X, in reality, since a plurality of UHPE monofilaments X are fused, the interface between adjacent UHPE monofilaments X may not appear clearly. It should also be noted that the drawn and fused UHPE monofilaments do not have a perfect circular shape in cross section. Liquid paraffin is present inside the UHPE fused yarn 5c (inside the yarn). That is, liquid paraffin is interposed between adjacent UHPE monofilaments. Note that the liquid paraffin inside the yarn is not interposed between all adjacent UHPE monofilaments, but is interposed in places. Furthermore, liquid paraffin is attached to the surface (yarn surface) of the UHPE fused yarn 5c. Note that the liquid paraffin on the yarn surface does not cover the entire yarn surface, but is present in places. In FIG. 9, the liquid paraffin present inside the yarn is marked with the symbol Y, and the liquid paraffin present on the yarn surface is marked with the symbol Z. The total amount of liquid paraffin is the sum of the amount of liquid paraffin inside the yarn and the amount of liquid paraffin on the surface of the yarn.

[0036] The single-filament fineness of the UHPE fusion yarn is not particularly limited, but if it is too small or too large, the fusion properties may decrease. From this viewpoint, the single-filament fineness of the UHPE fusion yarn is preferably 0.7 dtex or more and 2.5 dtex or less, more preferably 0.7 dtex or more and 2.2 dtex or less, and even more preferably 1.0 dtex or more and 1.5 dtex or less. The single filament fineness of the UHPE fused yarn refers to the value obtained by dividing the fineness of the UHPE multifilament (UHPE multifilament before fusion) by the draw ratio and then dividing the result by the number of filaments.

[0037] When the UHPE multifilament is twisted, a twisted UHPE fusion yarn is obtained. In this case, the twist coefficient K2 of the UHPE fusion yarn is not particularly limited, but is preferably more than 0 and not more than 2200, more preferably 400 to 2100, and even more preferably 900 to 2050. The UHPE fusion yarn having the twist coefficient K2 in the above range has a knot strength ratio a / b in the range of 0.9 to 1.1. The knot strength ratio (a / b) of the UHPE fusion yarn having a knot strength ratio of 0.9 to 1.1 is very small depending on the knotting method. The UHPE fusion yarn having a knot strength ratio in such a range can be suitably used as a fishing line. The twist coefficient K2 of the UHPE fusion yarn obtained from the UHPE multifilament in the form of simply pulling together a plurality of UHPE monofilaments is zero. The twist factor K2 of the UHPE fusion yarn is calculated by the formula 2: K2 = t × D 1 / 2 Here, t in the above formula 2 represents the number of twists (twists / m) of the UHPE fused yarn, and D in the above formula 2 represents the weight (unit: grams) of the fused yarn per 1000 m of length, excluding the amount of paraffin contained in the fused yarn.

[0038] The UHPE fusion yarn of the present invention has excellent fusibility and a low dynamic friction coefficient. The fusibility refers to the degree to which each monofilament constituting the UHPE multifilament before fusion is bonded to each other by fusion. The UHPE fusion yarn with excellent fusibility has a monofilament-like structure. Therefore, the UHPE fusion yarn of the present invention has good water drainage, excellent surface smoothness, is less likely to fluff when cut, and has excellent abrasion resistance.

[0039] [Technical significance of the present invention] Liquid paraffin functions as an auxiliary agent for bonding filaments together during the production of UHPE fused yarn. Specifically, the production of UHPE fused yarn is carried out in the order of the impregnation step, the fusion step, and the removal step, as described above. In the impregnation step, the UHPE multifilament is impregnated with liquid paraffin. In the fusion step, the heated liquid paraffin partially dissolves the surface of the filament, and the filaments are fused together in the fused portion by drawing. It is considered that liquid paraffin having an average molecular weight of 400 or more has excellent dissolving ability for the filaments. It is considered that the role of liquid paraffin is to dissolve the filaments during heating and drawing in the fusion step. Therefore, it can be said that the greater the amount of impregnation of liquid paraffin, the easier it is to proceed with dissolution, and a UHPE fused yarn with excellent fusion properties can be provided.

[0040] However, it has been found that when UHPE fused thread containing a large amount of liquid paraffin is used as fishing line, the fused thread can stick to the guide of the fishing rod, making it difficult to cast far, or the thread can become frayed (fraying is caused by some of the filaments in the multifilament coming loose). In this regard, liquid paraffin is thought to have the effect of lowering the dynamic friction coefficient like a lubricant, and therefore the inventors believed that a UHPE fusion yarn containing a large amount of liquid paraffin would be less likely to stick to a guide and would also be less likely to become frayed due to rubbing against the guide, etc.

[0041] Furthermore, after further intensive research, the inventors discovered that the liquid paraffin contained in the UHPE fused yarn is present both inside and on the surface of the fused yarn, and that the balance between the amount of liquid paraffin inside the yarn and the amount of liquid paraffin on the yarn surface is important. That is, as described above, the liquid paraffin present inside the yarn has the effect of dissolving the filaments during the production of the UHPE fused yarn, but does not contribute to the fusion power of the filaments. Therefore, the liquid paraffin present inside the manufactured UHPE fused yarn does not increase the fusion properties of the yarn. On the other hand, if a large amount of liquid paraffin is present inside the yarn, the liquid paraffin may swell during the use of the fused yarn, causing embrittlement of the fused parts of the filaments. The embrittlement of the fused parts of the filaments causes the filaments to come apart, which causes fluffing. Therefore, it is desirable for a UHPE fused yarn whose fusion properties do not decrease over time to have a small amount of liquid paraffin present inside the yarn. In addition, it is presumed that the presence of a large amount of liquid paraffin on the yarn surface causes the surface to become sticky, increasing the dynamic friction coefficient of the UHPE fused yarn. For these reasons, it is believed that a UHPE fused yarn having a total content of liquid paraffin of more than 0% by weight and not more than 13% by weight and a surface content of liquid paraffin of more than 0% by weight and not more than 10% by weight has filaments that are less likely to unravel even after long-term use (i.e., has excellent fusion properties even over time) and a low dynamic friction coefficient. This effect is also evident from the following examples and comparative examples.

[0042] The UHPE fusion yarn of the present invention can be used for various purposes such as fishing lines, fishing nets and other marine materials, ropes, strings for rackets, etc. The UHPE fusion yarn has a low dynamic friction coefficient, which reduces friction with rod guides, etc. Therefore, the UHPE fusion yarn can be particularly suitably used as a fishing line. EXAMPLES

[0043] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0044] <UHPE multifilament used> Multifilament (1): A multifilament made by twisting together 40 UHPE monofilaments, with a fineness of 85 dtex. Multifilament (2): A multifilament made by twisting together 20 UHPE monofilaments, with a fineness of 55 dtex. Multifilament (3): A multifilament made by twisting together 120 UHPE monofilaments, and a UHPE multifilament having a fineness of 275 dtex. Multifilament (4): A multifilament made by twisting together 240 UHPE monofilaments, and a UHPE multifilament having a fineness of 440 dtex. Multifilament (5): A multifilament made by twisting together 480 UHPE monofilaments, and a UHPE multifilament having a fineness of 880 dtex.

[0045] <Liquid paraffin used> Liquid paraffin: Four types of liquid paraffin with different average molecular weights as shown in the table. Manufactured by MORESCO.

[0046] <Measurement of molecular weight of liquid paraffin> The average molecular weight of liquid paraffin was calculated in terms of normal paraffin using a gas chromatograph (manufactured by Shimadzu Corporation, product name "GC-2010") from a calibration curve of the standard substance, normal paraffin (manufactured by SIGMA-ALDRICH, product name "ASTM5442 (C12-C60) Quantitative Linearity Standard"). Specifically, the standard substance, normal paraffin (manufactured by SIGMA-ALDRICH, product name "ASTM5442 (C12-C60) Quantitative Linearity Standard") was measured using a gas chromatograph (manufactured by Shimadzu Corporation, product name "GC-2010"), and a calibration curve was created from the retention time of the peak value of the standard substance and the molecular weight of the standard substance. Next, the liquid paraffin to be measured was similarly measured by gas chromatography. According to the principle of chromatography, the liquid paraffin moves to the detector at a retention time according to its molecular weight, and is then converted into an electrical signal by the detector. A chromatogram was obtained by plotting the time elapsed since the sample was introduced on the horizontal axis and the signal intensity obtained from the detector on the vertical axis, and the retention time of the peak value of that signal intensity was measured. The molecular weight of the liquid paraffin to be measured was determined from the retention time of this peak value and the above-mentioned calibration curve. An example of the measurement conditions for the gas chromatograph is shown below. Detector type: FID. Column: Capillary column (manufactured by Frontier Labs, product name "Ultra alloy-SIMDIS (HT)"). Length: 10 m, inner diameter: 0.53 mm, film thickness: 0.1 μm. Carrier gas: helium gas. Flow rate: 24.0 (ml / min), linear velocity: 140.5 cm / s. Initial column temperature: 35° C. Rate: 10° C. / min, final temperature: 410° C., detector temperature: 420° C. Injection method: total injection. Sample injection volume: 0.5 μl (microliter).

[0047] <Production equipment used> As shown in Figs. 6 and 7, a production apparatus 8 having a first line 81 and a second line 82 independent from each other was used. The impregnation device 63 and the excess removal device 64 of the first line 81 of the manufacturing apparatus 8 were of the type shown in FIG. 5. That is, the impregnation device 63 was of the type that brought a nonwoven fabric impregnated with liquid paraffin into contact with the surface of the UHPE multifilament, and the removal method of the excess removal device 64 was of the type that brought a dried nonwoven fabric into contact with the surface of the UHPE multifilament. The impregnation device 63 was provided with a supply unit 631 that continuously supplied liquid paraffin to the nonwoven fabric, and the supply unit 631 allowed the amount of liquid paraffin supplied to the nonwoven fabric to be arbitrarily set. In addition, the heating device 65 of the first line 81 was a unit consisting of two 5 m long ovens of the radiant heat type, and the stretching device was of the one-stage stretching type. Isopropyl alcohol, which is an organic solvent, is placed in bath 71 of second line 82 of this production equipment 8. In addition, heating device 72 of second line 82 was a single oven of a radiant heat type having a length of 5 m.

[0048] [Example 1] A multifilament was loaded into the yarn unwinding device 61 of the first line 81 of the manufacturing device 8 installed at room temperature (23° C.), and liquid paraffin having an average molecular weight of 483 was supplied to the impregnation device 63 as liquid paraffin (see FIGS. 5 and 6). The multifilament 5a was unwound from the yarn unwinding device 61, and the multifilament 5a was brought into contact with an impregnation section 633 made of a nonwoven fabric of the impregnation device 63, thereby coating the multifilament 5a with liquid paraffin, and then the excess liquid paraffin was removed from the multifilament 5a by the excess removal device 64. Furthermore, the multifilament 5a was stretched while being heated to about 155° C. by the heating device 65, thereby producing a fusion yarn precursor 5b. When the first line 81 was operated, the peripheral speed of the first stretching device 62 was set to 11.5 m / min and the peripheral speed of the second stretching device 66 was set to 24.2 m / min so that the stretching ratio would be about 2.1 times.

[0049] Next, the fusion yarn precursor 5b was loaded into the yarn unwinding device 69 of the second line 82 of the manufacturing apparatus 8, which was installed at room temperature (23°C) (see Fig. 7). The fusion yarn precursor 5b was unwound from the yarn unwinding device 69 and passed through a bath 71 filled with isopropyl alcohol to incompletely remove liquid paraffin on the surface of the fusion yarn precursor 5b, and then heated to about 100°C by a heating device 72 and wound up by a winding device 67 to produce the UHPE fusion yarn of Example 1. In the second line 82, the feed speed of the fusion yarn precursor 5b was set to 20 m / min, and the fusion yarn precursor 5b was passed through the bath 71 for about 2 seconds. In Table 1, "MF" stands for multifilament, and "FY" stands for UHPE fusion yarn (the same applies to Tables 2 to 5 below).

[0050] [Examples 2 to 7 and Comparative Examples 1 to 4] The UHPE fusion yarns of Examples 2 to 7 and Comparative Examples 1 to 4 were each produced in the same manner as in Example 1, except that at least one of the contact pressure of the multifilament 5a against the impregnation section 633 of the impregnation device 63 and the time for which the fusion yarn precursor 5b was passed through the isopropyl alcohol bath 71 was changed. Increasing the contact pressure of the multifilaments 5a against the impregnation section 633 of the impregnation device 63 increases the amount of liquid paraffin impregnated, and decreasing the contact pressure decreases the amount of liquid paraffin impregnated. In addition, increasing the time during which the fusion-yarn precursor 5b is passed through the isopropyl alcohol bath 71 increases the amount of liquid paraffin removed from the surface of the fusion-yarn precursor 5b, and decreasing the time decreases the amount of liquid paraffin removed from the surface of the fusion-yarn precursor 5b.

[0051] [Example 8] The UHPE fused yarn of Example 8 was produced in the same manner as in Example 1, except that liquid paraffin having an average molecular weight of 430 was used instead of the liquid paraffin having an average molecular weight of 483.

[0052] [Examples 9 to 14 and Comparative Examples 5 to 8] The UHPE fused yarns of Examples 9 to 14 and Comparative Examples 5 to 8 were each produced in the same manner as in Example 8, except that at least one of the contact pressure of the multifilament 5a against the impregnation section 633 of the impregnation device 63 and the time for which the fused yarn precursor 5b was passed through the isopropyl alcohol bath 71 was changed.

[0053] [Example 15] The UHPE fused yarn of Example 15 was produced in the same manner as in Example 1, except that liquid paraffin having an average molecular weight of 409 was used instead of the liquid paraffin having an average molecular weight of 483.

[0054] [Examples 16 to 21 and Comparative Examples 9 to 12] Except for changing at least one of the contact pressure of the multifilament 5a against the impregnation part 633 of the impregnation device 63 and the time for passing the fused yarn precursor 5b through the isopropyl alcohol bath 71, in the same manner as in Example 15, the UHPE fused yarns of Examples 16 to 21 and Comparative Examples 9 to 12 were produced respectively.

[0055] [Comparative Example 13] Except for using a liquid paraffin with an average molecular weight of 365 instead of the liquid paraffin with an average molecular weight of 483, in the same manner as in Example 1, the UHPE fused yarn of Comparative Example 13 was produced.

[0056] [Comparative Examples 14 to 25] Except for changing at least one of the contact pressure of the multifilament 5a against the impregnation part 633 of the impregnation device 63 and the time for passing the fused yarn precursor 5b through the isopropyl alcohol bath 71, in the same manner as in Comparative Example 13, the UHPE fused yarns of Comparative Examples 14 to 25 were produced respectively.

[0057] [Comparative Example 26] Except for not impregnating with liquid paraffin, in the same manner as in Example 1, the UHPE fused yarn of Comparative Example 26 was produced.

[0058] [Examples 22 to 25] Except for using MF(2) to (5) instead of MF(1) (see Table 5) and changing the peripheral speeds of the first drawing device 62 and the second drawing device, in the same manner as in Example 1, the UHPE fused yarns of Examples 22 to 25 were produced respectively.

[0059] <Measurement of Total Content Ratio of Liquid Paraffin in UHPE Fused Yarn> The content ratios of all the liquid paraffins contained in each UHPE fused yarn obtained in each example and comparative example were measured. Specifically, 100 m of the UHPE fused yarn of Example 1 was cut out, and its weight was measured in units of 0.1 mg. Separately, a yarn (hereinafter referred to as a control yarn) was produced in the same manner as in Example 1 except that liquid paraffin was not applied. 100 m of this control yarn was cut out, and its weight was measured in units of 0.1 mg. Then, the content rate of liquid paraffin in the UHPE fused yarn of Example 1 was determined by substituting into the following formula. The results are shown in Table 1. Similarly, 100 m of the UHPE fused yarns of Examples 2 to 25 and Comparative Examples 1 to 25 were each cut out, and their weights were measured in units of 0.1 mg. Separately, control yarns were produced in the same manner as in Examples 2 to 25 and Comparative Examples 1 to 25 except that liquid paraffin was not applied. 100 m of each of the control yarns of Examples 2 to 25 and Comparative Examples 1 to 25 was cut out, and its weight was measured in units of 0.1 mg. Then, the content rate of liquid paraffin in the UHPE fused yarns of Examples 2 to 25 and Comparative Examples 1 to 25 was determined by substituting into the following formula. The results are shown in Tables 1 to 5. Total content rate (weight %) of liquid paraffin in UHPE fused yarn = (M - N) / M × 100. However, M represents the weight of 100 m of the UHPE fused yarn of each Example and Comparative Example, and N represents the weight of 100 m of each control yarn.

[0060] <Measurement of content rate (surface content rate) of liquid paraffin present on yarn surface of UHPE fused yarn> The content rate of liquid paraffin on the yarn surface of each UHPE fused yarn obtained in each Example and Comparative Example was measured. Specifically, 100 m of the UHPE fused yarn of Example 1 was cut out, and its weight was measured in units of 0.1 mg. The 100 m of the UHPE fused yarn was immersed in 500 g of isopropyl alcohol at 20°C for 0.3 hours, then taken out and dried at 70°C for 10 minutes. By immersing in isopropyl alcohol, which is the removal liquid, for 0.3 hours, the paraffin wax present on the surface of the UHPE fused yarn can be almost completely removed. Hereinafter, the UHPE fused yarn with the surface paraffin wax completely removed is referred to as the removed yarn. The weight of 100 m of the removed yarn after drying was measured in units of 0.1 mg. From the weight of the UHPE fused yarn and the weight of the removed yarn, the surface content rate of the paraffin wax of the UHPE fused yarn of Example 1 was determined. The results are shown in Table 1. Similarly, 100 m of the UHPE fused yarns of Examples 2 to 25 and Comparative Examples 1 to 25 were each cut out, and their weights were measured in units of 0.1 mg. Each of the 100 m of the UHPE fused yarns of Examples 2 to 25 and Comparative Examples 1 to 25 was immersed in 500 g of isopropyl alcohol at 20°C for 0.3 hours, then taken out and dried at 70°C for 10 minutes. The weight of 100 m of the removed yarn after drying was measured in units of 0.1 mg. From the weight of the UHPE fused yarn and the weight of the removed yarn, the surface content rate of the paraffin wax of the UHPE fused yarns of Examples 2 to 25 and Comparative Examples 1 to 25 was determined. Their results are shown in Tables 1 to 5. Surface content rate of paraffin wax in UHPE fused yarn (wt%) = (M - V) / M × 100. However, M represents the weight of 100 m of the UHPE fused yarn of each example and comparative example, and V represents the weight of 100 m of each removed yarn. In addition, the internal content rate (the content rate of the paraffin wax present inside the yarn) is also shown in Tables 1 to 5. The internal content rate (wt%) was calculated as total content rate - surface content rate.

[0061] <Evaluation of the fusibility of UHPE fused yarn> The surface of each UHPE fused yarn obtained in each example and comparative example was visually observed, and each fused yarn was strongly rubbed with a finger to evaluate the degree of fusion of the filaments. Furthermore, it was evaluated whether it was suitable as a fishing line. The results are shown in the table. AA: The surface of the fused yarn was sufficiently smooth. Each monofilament was sufficiently fused, and the fused yarn did not come apart. It can be very suitably used as fishing line. A: The surface of the fused yarn was sufficiently smooth. Each monofilament was sufficiently fused, and the fused yarn hardly came apart. It can be suitably used as fishing line. B: The surface of the fused yarn was smooth. A part of the fused yarn (one or two places per 100 m) came apart slightly, and at that part, some monofilaments separated. It can be used as fishing line. C: Some irregularities were confirmed on the surface of the fused yarn. Many parts of the fused yarn (three or more places per 100 m) came apart, and at those parts, some monofilaments separated. It may be used as fishing line. D: Each monofilament constituting the multifilament was not fused, and all parts of each monofilament came apart, and it did not form the state of fused yarn. It can be evaluated that it cannot be used as fishing line.

[0062] <Measurement of the coefficient of kinetic friction of UHPE fused yarn> The coefficient of kinetic friction of each UHPE fused yarn obtained in each example and comparative example was measured according to JIS L 1015(2010)-8.13. As the measuring device, a yarn coefficient of kinetic friction measuring instrument manufactured by Dai-ichi Kagaku Seiki Co., Ltd. was used. The coefficient of kinetic friction μK is obtained by the following formula. The results are shown in a table. Note that the smaller the numerical value of the coefficient of kinetic friction, the smaller the frictional resistance and the easier it is to slide. Formula: μK = 0.733logW / (W - R) W: Load applied to both ends of the yarn (g) R: Reading of the U-gauge (g)

[0063] <Evaluation of yarn sticking property> The sticking properties of each UHPE fused yarn obtained in each example and comparative example were evaluated as follows. The UHPE fused yarn was wound around a fishing spool. Next, as shown in Fig. 10, a shaft member was fitted into the hole at the center of the spool, the shaft member was made horizontal, and with one hand holding the shaft member of the spool around which the UHPE fused yarn was wound, the spool was rotated around its axis in a direction opposite to the winding direction of the fused yarn. When the spool was rotated in this way, the situation when the wound fused yarn unwound from the spool was evaluated according to the following criteria. The results are shown in Tables 1 to 5. When the yarn unwound as the rotation progressed, the sticking property was evaluated as "none", and when the end of the fused yarn did not unwind and rotated together with the spool, the sticking property was evaluated as "present". In addition, when using a fused yarn with no sticking property as a fishing line, the release resistance from the spool becomes small. Therefore, it can be evaluated as a fused yarn that can be cast farther during casting.

[0064] <Evaluation of the handling property of UHPE fused yarn> The ease of handling when each UHPE fused yarn obtained in each example and comparative example was used as a fishing line was evaluated. The results are shown in Tables 1 to 5. ○: When using the fused yarn as a fishing line and casting the lure towards the water surface, the frictional resistance between the guide of the fishing rod and the fishing line was low, and it could be cast farther. Also, during casting 100 times per day, the fishing line did not break and the fishing line did not get caught in the guide of the fishing rod. ×: When using the fused yarn as a fishing line and casting the lure towards the water surface, the frictional resistance between the guide of the fishing rod and the fishing line was high, and it could not be cast very far. Also, during casting 100 times per day, the fishing line broke or the fishing line got caught in the guide of the fishing rod more than once.

[0065]

Table 1

[0066]

Table 2

[0067]

Table 3

[0068]

Table 4

[0069]

Table 5

[0070] The results of Examples 1 to 25 show that UHPE fusion yarns in which the total content of liquid paraffin with an average molecular weight of 400 or more is more than 0% and not more than 13% by weight, and the surface content is more than 0% and not more than 10% by weight, have good fusion properties, a low dynamic friction coefficient, and excellent handleability as fishing lines. In particular, a comparison of Examples 1 to 14 with Examples 15 to 21 shows that Examples 1 to 14, which contain liquid paraffin with a molecular weight of 420 or more, have even better fusion properties. Moreover, from the results of Comparative Examples 1 to 12, it can be seen that even when liquid paraffin having an average molecular weight of 400 or more is used, when the total content of liquid paraffin exceeds 13% by weight and / or the surface content of liquid paraffin exceeds 10% by weight, the dynamic friction coefficient is high and the thread stickiness and handleability are poor. The reason for the poor handleability is presumed to be that the liquid paraffin present in the fused part inside the thread swells and becomes embrittled while the fused thread is being cast, as in Comparative Example 24, even if the dynamic friction coefficient is small, localized destruction and fluffing progress rapidly due to the almost complete absence of paraffin on the thread surface, and the fused thread becomes more likely to become entangled in the fishing rod guide, resulting in poor handleability. [Industrial Applicability]

[0071] The ultra-high molecular weight polyethylene fusion yarn of the present invention can be used for fishery materials such as fishing lines, fishing nets, and longlines for leisure or fishing use, industrial materials such as ropes and kite lines, sports materials such as guts for tennis rackets and bowstrings, musical instrument materials such as guitar strings, threads for forming protective clothing, etc. In particular, the ultra-high molecular weight polyethylene fusion yarn of the present invention can be suitably used as fishing lines for leisure or fishing use. [Explanation of symbols]

[0072] 21,22,23,5a Ultra-high molecular weight polyethylene multifilament 3 Ultra-high molecular weight polyethylene monofilament 5b Fused yarn precursor 5c Ultra-high molecular weight polyethylene fusion yarn 6. Ultra-high molecular weight polyethylene fusion yarn manufacturing equipment

Claims

1. A fused yarn comprising ultra-high molecular weight polyethylene multifilaments and liquid paraffin with an average molecular weight of 400 or more, wherein the content of the liquid paraffin exceeds 0% by weight and is 8% by weight or less based on the whole yarn, and the content of the liquid paraffin present on the yarn surface exceeds 0% by weight and is 6% by weight or less, an ultra-high molecular weight polyethylene fused yarn.

2. The ultra-high molecular weight polyethylene fused yarn according to Claim 1, wherein the content of the liquid paraffin exceeds 0% by weight and is 5% by weight or less based on the whole yarn, and the content of the liquid paraffin present on the yarn surface exceeds 0% by weight and is 2% by weight or less.

3. The ultra-high molecular weight polyethylene fused yarn according to Claim 1, wherein the fineness of the fused yarn is 10 dtex or more and 500 dtex or less.

4. A method for producing an ultra-high molecular weight polyethylene fused yarn, which comprises ultra-high molecular weight polyethylene multifilaments and liquid paraffin with an average molecular weight of 400 or more, and wherein the content of the liquid paraffin exceeds 0% by weight and is 13% by weight or less based on the whole yarn, and the content of the liquid paraffin present on the yarn surface exceeds 0% by weight and is 10% by weight or less, comprising the steps of impregnating ultra-high molecular weight polyethylene multifilaments with liquid paraffin having an average molecular weight of 400 or more, obtaining a fused yarn precursor by heat-drawing the ultra-high molecular weight polyethylene multifilaments containing the liquid paraffin, and removing the liquid paraffin present on the surface of the fused yarn precursor by bringing the fused yarn precursor into contact with a removing liquid, a method for producing an ultra-high molecular weight polyethylene fused yarn.

Images