WO2019111830A1

WO2019111830A1 - Twisted yarn and twisted yarn structure using same

Info

Publication number: WO2019111830A1
Application number: PCT/JP2018/044309
Authority: WO
Inventors: 大高橋; 啓介滝島; 北村　一博
Original assignee: クラレトレーディング株式会社
Priority date: 2017-12-04
Filing date: 2018-11-30
Publication date: 2019-06-13
Also published as: TW201937024A; JP2019099990A; JP7249569B2

Abstract

A twisted yarn (1) has a core-sheath structure in which a core yarn (2) comprising a high-tensile-strength fiber is covered with a sheath yarn (3) comprising a thermoplastic fiber or a natural fiber. A differential core yarn twist coefficient K calculated by formula (1) is in the range of 0 to 60. K = T/(10,000/D)^1/2 (1) (where, D represents the total fineness (dtex) of the core yarn, T represents the absolute value (times/m) of (twist count of core yarn before sheath yarn is wound) – (twist count when core yarn and sheath yarn both are wound).)

Description

Twisted yarn and twisted yarn structure using the same

The present invention relates to a twisted yarn comprising a core yarn and a sheath yarn and used for a rope or the like, and a twisted yarn structure using the same.

In the past, as net products such as ropes and ball-proof nets, those obtained by twisting filaments of spun yarns or thermoplastic fibers consisting of single fibers such as natural fibers are used. Since it is used under severe conditions such as, it is desirable to have a high strength utilization rate as well as an excellent strength.

Therefore, those using high strength fibers have been proposed. For example, a high elongation fiber tow A such as polyester fiber and a high strength fiber tow B such as polyarylate fiber made of a molten liquid crystal polymer are mixed and twisted, and the ratio of elongation of tow A to tow B and the ratio of yarn length A rope set in a predetermined range has been proposed. And, it is described that such a configuration can provide a rope having an appropriate elongation and an excellent utilization factor of the strength (see, for example, Patent Document 1).

JP, 2010-121239, A

The high strength fiber described above has extremely high strength but low elongation, so to compensate for this decrease in elongation, it is necessary to blend and twist with the high elongation fiber as in the rope described in Patent Document 1 above. is there. However, in this case, there is a problem that the strength utilization factor of the twisted yarn is reduced due to the difference in physical properties between the high strength fiber and the high elongation fiber.

In addition, the above-mentioned high strength fiber has a large strength reduction due to ultraviolet light and abrasion, and further, when processed, there is a problem that the strength is reduced due to the change of the fiber shape.

Then, this invention is made in view of the above-mentioned problem, and an object of this invention is to provide the twist structure excellent in the intensity | strength and the strong utilization factor, and the same.

In order to achieve the above object, the twisted yarn of the present invention comprises a core yarn consisting of fibers having a strength of 15 cN / dtex and a thermoplastic yarn or a natural fiber, and is a sheath yarn twisted to cover the core yarn. The twisting coefficient K calculated by the following equation (1) is 0 to 60.

K = T / (10,000 / D) ^1/2 (1)
(Here, D is the total fineness (dtex) of the core yarn, T is (the number of twists of the core yarn before winding the sheath yarn)-(the number of twists when the core yarn and the sheath yarn are wound together) Is the absolute value (times / m) of

According to the present invention, it is possible to provide a twisted yarn excellent in strength and strength utilization rate and a twisted yarn structure using the same.

It is a perspective view showing the twisting yarn concerning the embodiment of the present invention. It is a sectional view showing a twist thread concerning an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. FIG. 1 is a perspective view showing a twisted yarn according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a twisted yarn according to an embodiment of the present invention.

As shown in FIG. 1 and FIG. 2, the twisted yarn 1 of the present invention is composed of a core yarn 2 consisting of high strength fibers, a thermoplastic fiber or a natural fiber, and a sheath yarn 3 twisted up so as to cover the core yarn 2 It is composed of

<High strength fiber>
Examples of high strength fibers constituting the core yarn 2 include high strength fibers such as polyarylate fibers made of a molten liquid crystal polymer, aramid fibers, ultra high molecular weight polyethylene fibers, and PBO (polyparaphenylene benzobisoxazole) fibers. In addition, inorganic fibers such as carbon fibers, alumina fibers, silicon carbide fibers, and glass fibers can also be used instead of these high strength fibers.

Further, from the viewpoint of securing the strength of the twisted yarn 1, a fiber having a strength of 15 cN / dtex or more is used as the high strength fiber.

In addition, the "strength" said by this invention says the thing of the tensile strength measured based on JISL1013.

Further, among the above-mentioned high strength fibers, polyarylate composed of a molten liquid crystal polymer, which is particularly low in water absorption, excellent in cut resistance, wear resistance, high strength, and difficulty in elongation under load (creep resistance). Fibers are particularly preferred.

The term "melt liquid crystal polymer" as used herein is mainly an aromatic polyester exhibiting optical anisotropy (liquid crystallinity) in the melt phase. For example, the sample is placed on a hot stage, and the temperature is raised under heating in a nitrogen atmosphere. And can be identified by observing the transmitted light of the sample.

The polyarylate composed of a molten liquid crystal polymer is, for example, composed of a repeating structural unit derived from an aromatic diol, an aromatic dicarboxylic acid, an aromatic hydroxycarboxylic acid or the like, and is an aromatic diol or aromatic unless the effect of the present invention is impaired. The structural units derived from dicarboxylic acid and aromatic hydroxycarboxylic acid are not particularly limited as to their chemical constitution. In addition, as long as the effects of the present invention are not impaired, the polyarylate made of a molten liquid crystal polymer may contain a structural unit derived from an aromatic diamine, an aromatic hydroxyamine or an aromatic aminocarboxylic acid. For example, examples shown in Table 1 can be given as preferable structural units.

In the constitutional units of Table 1, m is an integer of 0 to 2, and Y in the formula is each independently a hydrogen atom or a halogen atom (for example, a fluorine atom, or the like) within the range of 1 to the maximum substitutable number. An alkyl group (for example, an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, isopropyl group, t-butyl group, etc.), an alkoxy group (eg, methoxy group, ethoxy group, etc.) Group, isopropoxy group, n-butoxy group etc., aryl group (eg, phenyl group, naphthyl group etc.), aralkyl group [benzyl group (phenylmethyl group), phenethyl group (phenylethyl group) etc.], aryloxy group Examples include (for example, phenoxy group etc.), aralkyloxy groups (for example benzyloxy group etc.) and the like.

More preferable structural units include the structural units described in Examples (1) to (18) shown in Table 2, Table 3 and Table 4 below. In addition, when the structural unit in a formula is a structural unit which can show several structures, you may use it as a structural unit which comprises a polymer combining 2 or more types of such structural units.

In the constitutional units of Tables 2, 3 and 4, n is an integer of 1 or 2, and each constitutional unit n = 1, n = 2 may be present alone or in combination, Y ₁ and Y ₂ is each independently a hydrogen atom, a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., an alkyl group (eg, a methyl group, an ethyl group, an isopropyl group, a t-butyl group, etc.) Alkyl group of 1 to 4), alkoxy group (eg, methoxy group, ethoxy group, isopropoxy group, n-butoxy group etc.), aryl group (eg, phenyl group, naphthyl group etc.), aralkyl group [benzyl group (Phenylmethyl group), phenethyl group (phenylethyl group etc.), aryloxy group (eg phenoxy group etc.), aralkyloxy group (eg benzyloxy group etc.) etc It may be. Of these, a hydrogen atom, a chlorine atom, a bromine atom or a methyl group, are preferred.

Further, examples of Z include a substituent represented by the following formula.

The polyarylate composed of a molten liquid crystal polymer may preferably be a combination having a naphthalene skeleton as a constituent unit. In addition, it is particularly preferable to include both the hydroxybenzoic acid-derived structural unit (A) and the hydroxynaphthoic acid-derived structural unit (B). For example, as the structural unit (A), the following formula (A) can be mentioned, and as the structural unit (B), the following formula (B) can be mentioned, and from the viewpoint of improving melt formability, The ratio of the units (B) may preferably be in the range of 9/1 to 1/1, more preferably 7/1 to 1/1, and still more preferably 5/1 to 1/1.

In addition, the total of the structural unit of (A) and the structural unit of (B) may be, for example, 65 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol, with respect to all the structural units. It may be% or more. Among the polymers, preferred is a polyarylate composed of a molten liquid crystal polymer having 4 to 45% by mole of the constituent unit of (B).

The melting point of the molten liquid crystal polymer suitably used in the present invention is preferably in the range of 250 to 360 ° C., more preferably 260 to 320 ° C.

In addition, melting | fusing point here is the main absorption peak temperature observed and measured with a differential scanning calorimeter (DSC; Mettler "TA3000") based on a JIS K7121 test method. Specifically, after taking 10 to 20 mg of a sample in the above DSC apparatus and sealing it in an aluminum pan, flow 100 cc / min of nitrogen as a carrier gas and measure the endothermic peak when the temperature is raised at 20 ° C./min. . Depending on the type of polymer, if a clear peak does not appear in the 1st run in DSC measurement, raise the temperature to 50 ° C higher than expected flow temperature at a heating rate of 50 ° C / min, and at that temperature for 3 minutes After complete melting, it may be cooled to 50 ° C. at a temperature drop rate of 80 ° C./min, and then the endothermic peak may be measured at a temperature rise rate of 20 ° C./min.

Incidentally, the polyarylate comprising the above-mentioned molten liquid crystal polymer may be heat-treated such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyamide, polyphenylene sulfide, polyether ether ketone, fluorine resin or the like within the range not impairing the effects of the present invention. A plasticizing polymer may be added. In addition, inorganic substances such as titanium oxide, kaolin, silica and barium oxide, carbon black, colorants such as dyes and pigments, various additives such as antioxidants, ultraviolet light absorbers and light stabilizers may be included.

Next, a method for producing a polyarylate fiber comprising the above-described molten liquid crystal polymer will be described below. Polyarylate fibers made of a molten liquid crystal polymer can be fiberized by a common melt spinning method.

When fiberizing, the single fiber fineness is preferably 0.3 to 15 dtex, and more preferably 1 to 10 dtex. When the single fiber fineness is less than 0.3 dtex, inconveniences such as generation of fluff due to cutting of single fibers due to friction during production and generation of a defective place due to fusion between single fibers may occur. In addition, when the single fiber fineness exceeds 15 dtex, the touch becomes dull, and when the user's satisfaction can not be obtained or when producing a twisted yarn structure, the fiber's bundling property is lowered, and in the production process Problems may occur.

The number of filaments is preferably 2 to 10,000, and the total fineness is preferably 10 dtex to 50,000 dtex.

<Thermoplastic fiber, natural fiber>
Examples of the thermoplastic fiber forming the sheath yarn include polyester fiber, nylon fiber, polyethylene fiber, polypropylene fiber, polyvinyl alcohol fiber, vinylidene fiber and the like.

Moreover, as a natural fiber which forms a sheath yarn, cotton, wool (wool), silk, hemp etc. are mentioned. Among these, natural fibers such as cotton and wool are preferable because they are excellent in yarn strength and versatility.

These fibers are easy to obtain, economical and easy to handle. Moreover, according to the use etc. of the twisting structure manufactured using the twisting yarn 1, it can select suitably, and can be used individually or in combination of 2 or more types.

<Twisted yarn>
As shown in FIGS. 1 and 2, in the twisted yarn 1 of the present invention, a core yarn 2 consisting of high strength fibers is a sheath yarn 3 of a plurality (3 in the present embodiment) of thermoplastic fibers or natural fibers. It is covered by.

Further, in the twisted yarn 1 of the present invention, one multifilament may be used for the core yarn 2, or a bundle of multiple multifilaments may be used for the core yarn 2. In addition, the number of sheath yarns 3 is not particularly limited as long as it is plural.

Here, since the high strength fiber is an aggregate of single fibers whose orientations are uniformly aligned, when the high strength fibers are processed, the state in which the orientations are uniformly aligned becomes uneven, and each single fiber becomes uniform. Variations in the strength of the fibers occur. As a result, the strength of the high strength fiber as an aggregate is reduced.

Therefore, in the twisted yarn 1 of the present invention, the core yarn 2 made of high strength fiber has a core-sheath structure in which the sheath yarn 3 made of thermoplastic fiber or natural fiber is covered, and the sheath yarn 3 is wound around the core yarn 2 It has a structure.

With such a structure, even when a load is applied to the twisted yarn 1 due to an external factor, the influence of the orientation of the single fiber described above is alleviated, thus providing the twisted yarn 1 excellent in strength. It will be possible to

Moreover, since the core yarn 2 is protected by the sheath yarn 3 by such a core-sheath structure, direct irradiation of the core yarn 2 with ultraviolet light can be prevented, and the strength reduction due to the ultraviolet irradiation can be reduced. It can be suppressed. Moreover, since it is possible to suppress the wear of the core yarn 2, it is possible to suppress the strength reduction due to the wear.

Moreover, in the twisted yarn 1 of the present invention, since the core yarn 2 is covered with a plurality of sheath yarns 3, gaps between the sheath yarns 3 are difficult to form and can be uniformly covered.

Further, in the twisted yarn 1 of the present invention, as shown in FIG. 1, when the sheath yarn 3 is twisted in a state in which the core yarn 2 is covered by the sheath yarn 3, the core yarn 2 is twisted following the sheath yarn 3. Therefore, the number of twists of the core yarn 2 varies according to the number of twists of the sheath yarn 3 and the direction of twist, but the present inventors pay attention to this point and coat the core yarn 2 and the core yarn 2 In the twisting yarn 1 consisting of the sheath yarn 3 twisted as above, conditions were found for the strength of the twisting yarn 1 to exceed the strength of the core yarn alone (that is, the strength utilization rate is greater than 100%).

More specifically, the twisted yarn 1 of the present invention is characterized in that the draw-off core twisting coefficient K calculated by the following formula (1) is 0 to 60.

[Equation 1]
K = T / (10,000 / D) ^1/2 (1)
(Here, D is the total fineness (dtex) of the core yarn, T is (the number of twists of the core yarn before winding the sheath yarn)-(the number of twists when the core yarn and the sheath yarn are wound together) (twice / M) is an absolute value.)

And, by setting the draw-off core twisting coefficient K in the twisted yarn 1 in this range, the sum of the strengths of the high strength fibers constituting the core yarn 2 is maintained, so the strength of the core yarn 2 in the twisted yarn 1 is a sheath The strength of the core yarn alone not covered by the yarn 3 is exceeded, and it is possible to provide the twisted yarn 1 excellent in strength and strength utilization rate.

The total fineness of the core yarn 2 is preferably 10 to 50,000 dtex in one multifilament. If this is less than 10 dtex, it may be difficult to uniformly coat the core yarn 2 because the core yarn 2 is too thin, and if it exceeds 50,000 dtex, the alignment of the multifilaments tends to be impaired. This is because the physical properties may be easily varied.

The total fineness of the sheath yarn 3 is preferably 500 to 1,500 dtex in one multifilament. If the diameter is less than 500 dtex, it may be difficult to uniformly coat the core yarn 2 because the sheath yarn 3 is too thin, and if it exceeds 1,500 dtex, the sheath yarns 3 overlap with each other. This is because the amount of yarn 3 used may increase unnecessarily.

In addition, the number of twists of the core yarn 2 in the initial stage (before being made into a twisted yarn) is preferably 0 to 400 times / m. This is because if it exceeds 400 times / m, the alignment of the multifilaments is likely to be affected, so the orientation is impaired, and as a result, the mechanical properties against tension in the fiber axial direction may be lowered. It is for.

In addition, the sheath yarn 3 in the initial stage (prior to twisting) may be twisted or non-twisting. In particular, when the sheath yarn 3 is untwisted, the shape of the sheath yarn 3 is easily changed, so the contact between the core yarn 2 and the sheath yarn 3 becomes surface contact, and the tightening effect of the sheath yarn 3 on the core yarn 2 is easily exhibited. To be preferred.

Further, in the twisted yarn 1 of the present invention, the mixing ratio of the core yarn 2 to the whole of the twisted yarn 1 is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and still more preferably 30 to 70% by mass. is there. If the mixing ratio of the core yarn 2 is less than 10% by mass, the strength of the twisted yarn 1 may be insufficient. On the other hand, when the mixing ratio of the core yarn 2 exceeds 90% by mass, the cost is undesirably increased.

When the sheath yarn 3 is a span yarn (short fiber), when the core yarn 2 is covered with the sheath yarn 3, the shape of the sheath yarn 3 with respect to the core yarn 2 hardly changes, so the core yarn 2 and the sheath The contact of the yarn 3 is a point contact, and the tightening effect of the twisted yarn 3 on the core yarn 2 is less likely to be exhibited.

On the other hand, when the sheath yarn 3 is a multifilament (long fiber), the shape of the sheath yarn 3 is easily changed with respect to the core yarn 2, so the cross-sectional shape of the sheath yarn 3 tends to be flat. The contact between the sheath yarn 3 and the sheath yarn 3 makes a surface contact, and the tightening effect of the twisted yarn 3 on the core yarn 2 is easily exhibited. Therefore, since the contact part of the core yarn 2 and the sheath yarn 3 increases compared with the case where the sheath yarn 3 is a span yarn, it is considered that the strength utilization rate is improved.

<Production method of twisted yarn>
In the twisted yarn 1 of the present invention, for example, using a general twisting machine such as a double twister, a ring twister, an up twister, etc., a core yarn 2 consisting of one to plural multifilaments and a sheath yarn of plural multifilaments The twisted yarn 1 is formed by twisting 3 and 4 together.

Further, in the twisting yarn 1 of the present invention, the twisting direction of the composite twisting yarn (twisting direction in the twisting of the core yarn 2 and the sheath yarn 3) is not particularly limited, but generation of excessive twisting in the core yarn 2 is prevented From the viewpoint, it is preferable that the core yarn 2 be twisted in a non-twisted state or in a direction (reverse twist direction) that cancels the force in the twist direction of the sheath yarn 3.

For example, when twisting the core yarn 2 in the S direction at 47 times / m and twisting the sheath yarn 3 in the Z direction at 47 times / m, the core yarn 2 twists the sheath yarn 3 As a result, the initial twist number (47 twists / m in the S direction) is untwisted to 0 and the sheath / sheath 3 becomes a yarn with a core-sheath structure in which the sheath yarn 3 is twisted 47 times / m in the Z direction.

Thus, by adjusting the number of twists and the twist direction of the core yarn 2 before processing, the draw-off core twist coefficient of the core yarn 2 after processing (that is, the core after winding the core yarn 2 and the sheath yarn 3 together) It is possible to optimize the number of twists of the yarn 2).

Further, the length of the core yarn 2 can be obtained by uniformly covering and tightening the core yarn 2 by optimizing the number of filaments of the core yarn 2 to be used, the number of sheath yarns 3 and the single fiber fineness for each total denier. Since the orientation of single fibers constituting in the direction can be enhanced to minimize distortion, it is possible to maximize the strength.

<Twist structure>
The twisting structure formed by the twisting yarn 1 according to the present invention includes, for example, textile materials (for example, ball nets, nets such as animal nets, fishing nets and the like), ropes Ropes, marine ropes, underwater ropes, underwater ropes, playground equipment ropes, ship anchoring ropes, elevator ropes), braids, and shock absorbers.

Further, by using the twisted yarn 1 having the core and sheath of the present invention, even when the core yarn 2 is broken, it is possible to maintain the inherent strength of the sheath yarn 3.

Hereinafter, the present invention will be described based on examples. The present invention is not limited to these examples, and these examples can be modified or changed based on the spirit of the present invention, and those are excluded from the scope of the present invention is not.

Example 1
<Preparation of twisted yarn>
First, prepare one yarn (total fineness: 1670 dtex) consisting of a polyarylate fiber (made by Kuraray Co., Ltd., trade name: Bectran (registered trademark)) made of a molten liquid crystal polymer so that it becomes 47 times / m in the S direction The core yarn was prepared by

Next, three yarns (total fineness: 830 × 3 = 2490 dtex) consisting of polyethylene terephthalate fibers (manufactured by Teijin Ltd., trade name: P902F 830T / 72F) are prepared and manufactured. The core yarn and the sheath yarn were entirely twisted in the Z direction so as to be 47 times / m in the Z direction to prepare a twisted yarn of a core-sheath structure.

<Measurement of tensile strength of twisted yarn>
A yarn of a predetermined length (20 cm effective length secured) is cut out from the produced twisted yarn, and this is used as a sample yarn, and in accordance with JIS L1013, using a tensile load measuring machine (trade name: RTG1310 made by A and D) The tensile strength [N] of the twisted yarn was measured under the conditions of a temperature of 20 ° C. and a humidity of 65% RH. The above results are shown in Table 5.

(Example 2)
The above-described embodiment is carried out except that the core yarn is produced by twisting 217 times / m in the S direction, and the entire core yarn and sheath yarn is twisted 217 times / m in the Z direction. In the same manner as Example 1, a twisted yarn with a core-sheath structure was produced.

Then, the tensile strength of the twisted yarn was measured in the same manner as in Example 1 described above. The above results are shown in Table 5.

(Example 3)
The above-mentioned practice is carried out except that the core yarn is produced by twisting in the S direction 136 times / m and producing the core yarn and the sheath yarn in the Z direction 62 times / m. In the same manner as Example 1, a twisted yarn with a core-sheath structure was produced.

(Example 4)
The above-described embodiment is carried out except that the core yarn is produced by twisting 340 times / m in the S direction and the whole of the core yarn and the sheath yarn is twisted 217 times / m in the Z direction. In the same manner as Example 1, a twisted yarn with a core-sheath structure was produced.

(Example 5)
The above-described embodiment is carried out except that the core yarn is produced by twisting so as to be 364 times / m in the S direction and that the whole of the core yarn and the sheath yarn is so twisted as 217 times / m in the Z direction. In the same manner as Example 1, a twisted yarn with a core-sheath structure was produced.

(Example 6)
First, prepare three yarns (total fineness: 1670 × 3 = 5010 dtex) consisting of polyarylate fibers (made by Kuraray Co., Ltd., trade name: Bectran (registered trademark)) made of a molten liquid crystal polymer, The core yarn was produced by twisting in the S direction so as to be 46 times / m.

Next, 6 yarns (total fineness: 830 × 6 = 4980 dtex) consisting of polyethylene terephthalate fibers (manufactured by Teijin Ltd., trade name: P902F 830T / 72F) are prepared and prepared. The core yarn and the sheath yarn were entirely twisted in the Z direction so as to be 116 times / m in the Z direction to prepare a twisted yarn of a core-sheath structure.

(Example 7)
First, prepare three yarns (total fineness: 1670 tex) consisting of para-aramid fibers (manufactured by DuPont, trade name: Kevlar 29) (total fineness: 1670 × 3 = 5010 dtex) and prepare 46 times / m in the S direction The core yarn was prepared so as to be

(Example 8)
First, prepare a yarn (total fineness: 1760 dtex) consisting of ultra high molecular weight polyethylene fiber (made by Toyobo Co., Ltd., trade name: Dyneema), twist it so that it becomes 90 times / m in the S direction, and core yarn Made.

Next, three yarns (total fineness: 830 × 3 = 2490 dtex) consisting of polyethylene terephthalate fibers (manufactured by Teijin Ltd., trade name: P902F 830T / 72F) are prepared and manufactured. The core yarn and the sheath yarn were entirely twisted in the Z direction so as to be 90 times / m in the Z direction to prepare a twisted yarn with a core-sheath structure.

(Comparative example 1)
A single yarn (total fineness: 1670 dtex) consisting of a polyarylate fiber (made by Kuraray Co., Ltd., trade name: Bectran (registered trademark)) made of a molten liquid crystal polymer is prepared and twisted so as to be 74 times / m in the S direction. , Produced a twisted yarn.

(Comparative example 2)
First, prepare a yarn (total fineness: 1670 dtex) consisting of a polyarylate fiber (made by Kuraray Co., Ltd., trade name: Bectran (registered trademark)) made of a molten liquid crystal polymer so that it becomes 420 times / m in the S direction To produce a twisted yarn.

Next, three yarns (total fineness: 830 × 3 = 2490 dtex) consisting of polyethylene terephthalate fibers (manufactured by Teijin Ltd., trade name: P902F 830T / 72F) are prepared and manufactured. The core yarn and the sheath yarn were twisted in the Z direction so as to be 248 times / m in the Z direction to prepare a twisted yarn with a core-sheath structure.

(Comparative example 3)
First, prepare three yarns (total fineness: 1670 × 3 = 5010 dtex) consisting of polyarylate fibers (made by Kuraray Co., Ltd., trade name: Bectran (registered trademark)) made of a molten liquid crystal polymer, A twisted yarn was produced by twisting 81 times / m in the S direction.

(Comparative example 4)
First, prepare three yarns (total fineness: 1670 tex) consisting of para-aramid fibers (manufactured by DuPont, trade name: Kevlar 29) (total fineness: 1670 × 3 = 5010 dtex) and prepare 81 times / m in the S direction The resultant was twisted to prepare a twisted yarn.

(Comparative example 5)
First, one yarn (total fineness: 1760 dtex) made of ultra-high molecular weight polyethylene fiber (manufactured by Toyobo Co., Ltd., trade name: Dyneema) is prepared, and is twisted at 80 times / m in the S direction to prepare twisted yarn. did.

As shown in Table 5, in the twisted yarns of Examples 1 to 5 in which the draw-off core twisting coefficient K is in the range of 0 to 60, only polyarylate fibers consisting of the molten liquid crystal polymer forming the core yarns of Examples 1 to 5 It is understood that the tensile strength is improved and the strength is excellent as compared with the twisted yarn of the comparative example 1 (twist number is 74).

Also, the strength utilization factor of each of the twisted yarns of Examples 1 to 5 (ie, (Tensile strength of the twisted yarn of any of Examples 1 to 5 / tensile strength of the twisted yarn of Comparative Example 1) x 100) is more than 100%. You can see that it is getting bigger.

Similarly, in the twisted yarn of Example 6, the tensile strength is higher than that of the twisted yarn of Comparative Example 3 (twist number is 81) consisting only of polyarylate fibers consisting of the molten liquid crystal polymer forming the core yarn of Example 6. Is improved and it is understood that the strength is excellent. In addition, it can be seen that the strength utilization factor of the twisted yarn of Example 6 (that is, (Tensile strength of twisted yarn of Example 6 / tensile strength of twisted yarn of Comparative Example 3) × 100) is greater than 100%.

Moreover, in the twisted yarn of Example 7, compared with the twisted yarn (twist number 81) of Comparative Example 4 consisting only of para-aramid fibers forming the core yarn of Example 7, the tensile strength is improved, and the strength is higher. It is clear that it is excellent. In addition, it can be seen that the strength utilization factor of the twisted yarn of Example 7 (that is, (Tensile strength of twisted yarn of Example 7 / Tensile strength of twisted yarn of Comparative Example 4) x 100) is greater than 100%.

Furthermore, in the twisted yarn of Example 8, the tensile strength is improved as compared to the twisted yarn (twist number is 80) of Comparative Example 5 consisting only of the ultrahigh molecular weight polyethylene fiber forming the core yarn of Example 8, It can be seen that the strength is excellent. In addition, it can be seen that the strength utilization factor of the twisted yarn of Example 8 (that is, (Tensile strength of twisted yarn of Example 8 / tensile strength of twisted yarn of Comparative Example 5) x 100) is greater than 100%.

In addition, in the twisting yarn of Comparative Example 2, since the draw-off core twisting coefficient K is larger than 60, the twisting yarn of Comparative Example 1 consisting of only polyarylate fibers consisting of a molten liquid crystal polymer forming the core yarn of Comparative Example 2 (twist number The result is inferior in strength and strong utilization compared to 74).

As described above, the present invention is composed of a core yarn and a sheath yarn, and is suitable for a twisting yarn used for a rope or the like.

1 Twisted yarn 2 Core yarn 3 Sheath yarn

Claims

It is a twisted yarn comprising a core yarn comprising fibers having a strength of 15 cN / dtex or more, and a sheath yarn comprising thermoplastic fibers or natural fibers and being twisted so as to cover the core yarn,
A twisted yarn characterized in that a draw-off core twisting factor K calculated by the following formula (1) is 0 to 60.
K = T / (10,000 / D) 1/2 (1)
(Here, D is the total fineness (dtex) of the core yarn, T is (the number of twists of the core yarn before winding the sheath yarn)-(the number of twists when the core yarn and the sheath yarn are wound together) It is a value (times / m).
The twisted yarn according to claim 1, wherein the core yarn is covered with a plurality of the sheath yarns.
The fiber is at least one selected from the group consisting of polyarylate fiber, aramid fiber, polyethylene fiber, polyparaphenylene benzoxazole (PBO) fiber, carbon fiber, and glass fiber made of a molten liquid crystal polymer. The twisted yarn according to claim 1 or claim 2.
The thermoplastic fiber is at least one selected from the group consisting of polyester fiber, nylon fiber, polyethylene fiber, polypropylene fiber, polyvinyl alcohol fiber, and vinylidene fiber, and the natural fiber is cotton, wool (wool), 4. The twisted yarn according to any one of claims 1 to 3, which is at least one selected from the group consisting of silk and hemp.
A twisting structure comprising the twisting yarn according to any one of claims 1 to 4.