TW201937024A - Twisted yarn and twisted yarn structure using same - Google Patents

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

Crepe and crepe structure made of the crepe

The present invention relates to a crepe composed of a core yarn and a sheath yarn and used for manufacturing a rope or the like and a crepe structure made of the crepe.

In the prior art, a spun yarn spun from a single fiber such as a natural fiber or a filament obtained by twisting a filament of a thermoplastic fiber is generally used to manufacture a net product such as a rope and a ball net, because such a rope is tied to a high load. It is used under severe conditions such as under load, so the strength and strength efficiency of the ideal rope are high.

For example, the content disclosed in Patent Document 1 is as follows. A rope made of high-strength fibers has been proposed. For example, the proposed rope is a ratio of the elongation of the fiber bundle A to the fiber bundle B by a high-strength fiber bundle B such as a high-stretch fiber bundle A such as a mixed polyester fiber and a polyarylate fiber formed of a molten liquid crystal polymer. And the ratio of the length of the fiber is set within a prescribed range. It is also disclosed that it is possible to provide a rope which has a moderate degree of elongation and excellent strength utilization efficiency by the above structure.

Patent Document 1 Japanese Patent Laid-Open Publication No. 2010-121239

The high-strength fiber is extremely high in strength but extremely low in elongation. Therefore, in order to compensate for the disadvantage that the elongation is low, it is necessary to mix the high-strength fiber with the high-stretch fiber as in the rope disclosed in Patent Document 1 above. However, in this case, the poor physical properties of the high-strength fiber and the high-stretch fiber cause a decrease in the strength utilization of the crepe.

Further, the strength of the above-mentioned high-strength fiber due to ultraviolet rays or abrasion is severely deteriorated, and if it is processed, the change in fiber shape causes a decrease in strength.

Therefore, the present invention has been completed in view of the above problems. The object of the invention is to provide a crepe having a high strength and a strong utilization rate and a crepe structure made of the crepe.

In order to achieve the above object, the crepe yarn of the present invention is composed of a core yarn spun from a fiber having a strength of 15 cN/dtex or more and a sheath yarn spun from a thermoplastic fiber or a natural fiber and coated with a core yarn. It is characterized in that the net core coefficient K calculated by the following formula (1) is 0 to 60.

K=T/(10,000/D) ^1/2 (1)

(where D is the total fineness of the core yarn, the unit is dtex, T is the (twist of the core yarn before winding the sheath yarn) - (the twist of the core yarn and the sheath yarn after winding) (back /m).)

According to the present invention, it is possible to provide a crepe yarn having high strength and high power utilization efficiency and a crepe structure made of the crepe yarn.

1‧‧‧ crepe

2‧‧‧core yarn

3‧‧‧sheath

Fig. 1 is a perspective view showing a crepe of an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a crepe of an embodiment of the present invention.

The invention is described in detail below. 1 is a perspective view showing a crepe according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a crepe 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 a core yarn 2 spun from high-strength fibers and a sheath yarn 3 spun from thermoplastic fibers or natural fibers and coated with a core yarn 2. Composition.

<High-strength fiber>

The high-strength fibers spun into the core yarn 2 are, for example, polyarylate fibers formed of a molten liquid crystal polymer, aramid fibers, ultrahigh molecular weight polyethylene fibers, and PBO (polyp-phenylenebenzobisoxazole: poly p-phenylenebenzobisoxazole) ) High strength fibers such as fibers. Further, inorganic fibers such as carbon fibers, alumina fibers, strontium carbide fibers, and glass fibers can be used instead of these high-strength fibers.

From the viewpoint of securing the strength of the crepe 1, the high-strength fiber is a fiber having a strength of 15 cN/dtex or more.

Further, the "strength" as used in the present invention means the tensile strength measured in accordance with JIS L1013.

Particularly preferred among the above high-strength fibers are polyarylate fibers formed of a molten liquid crystal polymer. Among them, the polyarylate fiber has a particularly low water absorption rate, is excellent in cut resistance, scratch resistance, and abrasion resistance, and has high strength and is difficult to stretch when the load continues to act (excellent creep resistance).

In addition, the "melted liquid crystal polymer" as used herein mainly means an aromatic polyester which exhibits optical anisotropy (liquid crystallinity) in a molten phase. For example, the sample is placed on a hot stage, heated in a nitrogen atmosphere to raise the temperature, and it is possible to determine whether or not the liquid crystal property is exhibited by observing the transmitted light passing through the sample.

The polyaromatic ester formed of the molten liquid crystal polymer is composed of, for example, a repeating structural unit derived from an aromatic diol, an aromatic dihydroxy acid, an aromatic hydroxycarboxylic acid or the like. The chemical structure derived from the structural unit of the aromatic diol, the aromatic dihydroxy acid, and the aromatic hydroxycarboxylic acid is not particularly limited as long as the effects of the present invention are not impaired. The polyaromatic ester formed of the molten liquid crystal polymer may further contain a structural unit derived from an aromatic diamine, an aromatic hydroxylamine or an aromatic aminocarboxylic acid, within a range not affecting the effects of the present invention. For example, preferred structural units have the examples shown in Table 1.

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

More preferable structural units include structural units disclosed in the following examples (1) to (18) shown in Tables 2 and 3 and Table 4 below. Further, if the structural unit in the formula is a structural unit capable of exhibiting a plurality of structures, two or more such structural units may be combined to be used as a structural unit forming a polymer.

Table 2

table 3

In the structural units of Table 2, Table 3, and Table 4, n is an integer of 1 or 2, and each structural unit n=1 and n=2 may exist alone or in combination. Y ₁ and Y ₂ may also be independently and respectively have a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), or the like, and an alkyl group (for example, methyl group, ethyl group, isopropyl group, or tertiary group). An alkyl group having 1 to 4 carbon atoms such as a butyl group, an alkoxy group (e.g., a methoxy group, an ethoxy group, an isopropoxy group, a n-butoxy group, etc.) or an aryl group (e.g., a phenyl group, a naphthyl group, etc.) An aralkyl group [benzyl (phenylmethyl), phenethyl (phenylethyl) or the like], an aryloxy group (for example, a phenoxy group), an aralkyloxy group (for example, a benzyloxy group), or the like. It is preferably a hydrogen atom, a chlorine atom, a bromine atom or a methyl group in the above.

Z has, for example, a substituent represented by the following formula.

Preferably, the polyaromatic ester formed from the molten liquid crystal polymer is a combination of a naphthalene skeleton as a structural unit. Further, it is particularly preferred to contain both a structural unit (A) derived from hydroxybenzoic acid and a structural unit (B) derived from hydroxynaphthoic acid. For example, the structural unit (A) may be exemplified by the following formula (A), and the structural unit (B) may be exemplified by the following formula (B). From the viewpoint of improving melt formability, the ratio of the structural unit (A) to the structural unit (B) is preferably in the range of 9/1 to 1/1, and more preferably in the range of 7/1 to 1/1. It is especially good in the range of 5/1~1/1.

Preferably, the total of the structural unit of (A) and the structural unit of (B) is 65 mol% or more, more preferably 70 mol% or more, and particularly preferably 80 mol%, relative to all structural units. the above. Preferably, it is a polyaromatic ester formed from a molten liquid crystal polymer of 4 to 45 mol% of the structural unit of the polymer (B).

Preferably, the melting point of the molten liquid crystal polymer suitable for use in the present invention is in the range of 250 to 360 ° C, more preferably in the range of 260 to 320 ° C.

In addition, the melting point referred to here is the main absorption peak temperature observed by a differential scanning calorimeter (DSC: "TA3000" manufactured by METTLER TOLEDO Co., Ltd.) in accordance with the test method in JIS K7121. Specifically, 10 to 20 mg of the sample was sealed in an aluminum sample pan, and after they were placed together in the DSC device, nitrogen gas was introduced as a carrier gas at a rate of 100 cc/min, and measured at 20 ° C / min. An endothermic peak at a rate increase. Due to the type of polymer, the first time (1st run) did not show a clear peak in the DSC measurement, and the temperature was raised to 50 ° C / min. It is 50 ° C higher than the expected flow temperature, and after completely melting at this temperature for 3 minutes, it is cooled to 50 ° C at a cooling rate of 80 ° C / minute, and then the endothermic peak is measured at a heating rate of 20 ° C / minute. Just fine.

Further, polyethylene terephthalate or modified polyethylene terephthalate may be added to the above-mentioned polyaromatic ester formed of a molten liquid crystal polymer within a range that does not impair the effects of the present invention. A thermoplastic polymer such as polyolefin, polycarbonate, polyamide, polyphenylene sulfide, polyetheretherketone or fluorocarbon resin. The polyaromatic ester formed of the molten liquid crystal polymer may further contain an inorganic substance such as titanium oxide, kaolin, cerium oxide or cerium oxide, a coloring agent such as carbon black, a dye or a pigment, an antioxidant, an ultraviolet absorbing agent, and a light stabilizer. And other additives.

The above preparation method of the polyarylate fiber formed of the molten liquid crystal polymer will be described below. The polyarylate fibers formed from the molten liquid crystal polymer can be fiberized by a conventional melt spinning method.

In the case of fibrillation, the single fiber fineness is preferably from 0.3 to 15 dtex, more preferably from 1 to 10 dtex. When the single fiber fineness is less than 0.3 dtex, the following problems may occur: the single fibers are broken and fluffed due to friction during preparation, and the defective portions due to fusion of the single fibers are generated. If the single fiber fineness is more than 15 dtex, the following disadvantages may occur: the hand feel is rough and the user is not satisfied; when the crepe structure is spun, the bundleability of the fiber is lowered, and a bad phenomenon occurs in the spinning process.

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

<thermoplastic fiber, natural fiber>

The thermoplastic fibers forming the sheath yarn are, for example, polyester fibers, nylon fibers, polyethylene fibers, polypropylene fibers, polyvinyl alcohol fibers, vinylidene fibers, and the like.

The natural fibers forming the sheath yarn are, for example, cotton, wool, silk, hemp, and the like. Natural fibers such as cotton and wool have high strength and versatility, and are preferably natural fibers such as cotton and wool.

These fibers are readily available and economical and easy to handle. These fibers can be appropriately selected in accordance with the use of the crepe structure 1 made of the crepe yarn 1, and the like, and these fibers may be used singly or in combination of two or more.

<捻纱>

As shown in Fig. 1 and Fig. 2, the crepe yarn 1 of the present invention is coated with a core of a high-strength fiber by a plurality of (three in the present embodiment) sheath yarns 3 spun from thermoplastic fibers or natural fibers. Gain 2 is obtained.

In the crepe 1 of the present invention, one multifilament may be used as the core yarn 2, or a plurality of multifilaments may be used as the core yarn 2. The number of the sheath yarns 3 is not particularly limited as long as it has a plurality of roots.

Here, the high-strength fiber is a single-fiber aggregate having the same orientation. When the high-strength fiber is processed, the state in which the orientation is the same is changed to a different state, and the strength of each single fiber varies. As a result, the strength of the high-strength fiber as an aggregate decreases.

Therefore, the crepe 1 of the present invention is a core-sheath structure obtained by coating a core yarn 2 spun from a high-strength fiber with a sheath yarn 3 formed of a thermoplastic fiber or a natural fiber, that is, a core yarn 2 is used. The structure in which the sheath yarn 3 is wound is wound.

With such a configuration, even when a load is applied to the crepe 1 by external causes, the influence of the orientation of the above-mentioned single fibers is reduced, so that the high-strength crepe 1 can be provided.

Further, since the core yarn 2 is protected by the sheath yarn 3 by the core sheath structure, it is possible to prevent the ultraviolet rays from directly irradiating onto the core yarn 2, and it is possible to suppress the decrease in strength due to the ultraviolet rays. It is also possible to suppress the abrasion of the core yarn 2, and therefore it is also possible to suppress the decrease in strength due to abrasion.

In the specific state of the crepe 1 of the present invention, the core yarn 2 is covered with the plurality of sheath yarns 3, so that it is difficult to form a gap in the sheath yarn 3, and the core yarn 2 can be uniformly covered.

As shown in Fig. 1, in the twisted yarn 1 of the present invention, the sheath yarn 3 is twisted while the core yarn 2 is covered with the sheath yarn 3, and the core yarn 2 is twisted with the sheath yarn 3. Therefore, the twist of the core yarn 2 changes depending on the twist and the twist of the sheath yarn 3. The present inventors have focused on this point and found that the strength of the crepe 1 composed of the core yarn 2 and the sheath yarn 3 formed by coating the core yarn 2 is greater than the strength of the core yarn unit (i.e., strong use). The condition is greater than 100%).

More specifically, the twisted yarn 1 of the present invention is characterized in that the net core twist factor K calculated by the following formula (1) is 0 to 60.

[Formula 1] K=T/(10,000/D) ^1/2 (1)

(where D is the total fineness (dtex) of the core yarn, T is (the twist of the core yarn before winding the sheath yarn) - (the twist after the core yarn and the sheath yarn have been wound) (back / m) Absolute value.)

Further, by setting the net core yarn twist coefficient K of the twisted yarn 1 within this range, the total strength of the high-strength fibers of the spun yarn 2 is maintained, and therefore, the strength of the core yarn 2 in the twisted yarn 1 is The strength of the core yarn unit which is not covered by the sheath yarn 3 is greater, so that the twist yarn 1 having high strength and high power utilization ratio can be provided.

In terms of the total fineness of the core yarn 2, one multifilament yarn is preferably from 10 to 50,000 dtex. This is because, in the case of less than 10 dtex, the core yarn 2 is too fine, so that it is sometimes difficult to uniformly coat the core yarn 2; if it is more than 5,000 dtex, the tensile property (parallelism) of the multifilament is easily broken, and the physical properties are sometimes deteriorated. It is easy to produce deviations.

In terms of the total fineness of the sheath yarn 3, one multifilament yarn is preferably 500 to 1,500 dtex. This is because, in the case of less than 500 dtex, the sheath yarn 3 is too thin, so that it is sometimes difficult to uniformly coat the core yarn 2; if it is more than 1,500 dtex, the sheath yarns 3 overlap each other, and the amount of the sheath yarn 3 is sometimes unnecessary. Increase in land.

The twist of the core yarn 2 initially (before the formation of the crepe) is preferably from 0 to 400 rpm. This is because if it is more than 400 times/m, the tensile property (parallelism) of the multifilament is easily affected, and the orientation is deteriorated, and eventually the mechanical properties of the stretching with respect to the axial direction of the fiber may be lowered.

The sheath yarn 3 (before the formation of the crepe) can be either a crepe or a crepe-free yarn. In particular, in the case where the sheath yarn 3 is crepe-free, the shape of the sheath yarn 3 is liable to change, so that the contact of the core yarn 2 with the sheath yarn 3 is Since the surface contact is easy to exert the tightening effect of the sheath yarn 3 on the core yarn 2, it is preferable.

In the crepe 1 of the present invention, the mixing ratio of the core yarn 2 to the entire crepe 1 is preferably from 10 to 90% by mass, more preferably from 20 to 80% by mass, even more preferably from 30 to 70% by mass. 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, if the mixing ratio of the core yarn 2 is more than 90% by mass, the cost becomes high, which is not preferable.

When the sheath yarn 3 is a short fiber and a twisted yarn (short fiber), if the core yarn 2 is covered with the sheath yarn 3, the shape of the sheath yarn 3 is hard to change with respect to the core yarn 2, and the core yarn 2 and the sheath yarn 3 are not changed. When the contact is a point contact, it is difficult for the crepe 3 to exert a firming effect on the core yarn 2.

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 that the cross-sectional shape of the sheath yarn 3 is easily changed into a flat shape, and the core yarn 2 and the sheath yarn are easily formed. The contact of 3 is in surface contact, and the twisted yarn 3 tends to exert a firming effect on the core yarn 2. Therefore, it can be considered that the core yarn 2 has a large contact portion with the sheath yarn 3 as compared with the case where the sheath yarn 3 is a short fiber twisted yarn, and thus the strength utilization rate is improved.

<Spinning method of crepe>

The crepe yarn 1 of the present invention is, for example, a general twisting machine such as a double twister, a ring twister, or an uptwister, and will be composed of one to several roots. The core spun yarn 2 is combined with a plurality of multifilament yarns 3.

In the twisted yarn 1 of the present invention, the twist of the composite twisted yarn (the twist direction when the core yarn 2 and the sheath yarn 3 are twisted) is not particularly limited. From the viewpoint of preventing excessive twisting of the core yarn 2, the core yarn 2 is preferably in a flawless state. Alternatively, it is preferable to twist the core yarn 2 in a direction (reverse direction) which counteracts the direction of the force of the sheath yarn 3.

For example, in the case where the core yarn 2 is twisted at 47 times/m in the S direction and the sheath yarn 3 is twisted at 47 times/m in the Z direction, the core yarn 2 is twisted by the sheath yarn 3, whereby the initial twist ( The twisted 47 times/m in the S direction is untwisted and returned to zero, thereby becoming a yarn having a core sheath structure in which the sheath yarn 3 is twisted by 47 times/m in the Z direction.

In this manner, by adjusting the twist and the twist of the core yarn 2 before processing, the net core yarn twist coefficient of the processed core yarn 2 (that is, the core yarn after the core yarn 2 and the sheath yarn 3 have been wound can be realized). 2 捻)) optimization.

The number of filaments of the core yarn 2 to be used, the number of the sheath yarns 3 for each total fineness, and the single fiber fineness are optimized, and the core yarn 2 is uniformly coated and tightened, whereby the core yarn 2 can be improved. The orientation of the single fibers spun into the core yarn 2 in the longitudinal direction minimizes the strain, so that the strength can be maximized.

<crepe structure>

The crepe structure made of the crepe 1 of the present invention is, for example, a fiber material used in the aquaculture and civil engineering industries (for example, net products such as a net for blocking the net, an anti-beat net, and a fishing net), and a rope (a rope for land, Marine ropes, ropes for the sea, ropes for water, ropes for amusement equipment, ropes for ship fixing, ropes for elevators, Japanese traditional ropes and impact absorbing materials.

By using the twisted yarn 1 having the core sheath of the present invention, even if the core yarn 2 is broken, the inherent strength of the sheath yarn 3 can be maintained.

[Examples]

The invention is illustrated below with reference to the examples. Further, the present invention is not limited to the embodiments, and modifications and changes can be made to the embodiments based on the gist of the present invention, and the modifications or variations are not excluded from the scope of the present invention.

(Example 1) <Spinning of crepe>

First, one yarn (total fineness: 1670 dtex) spun with a polyarylate fiber (manufactured by Kuraray Co., Ltd., trade name: Vectran (registered trademark)) formed of a molten liquid crystal polymer was prepared in the S direction. 47 times / m twisted, spinning core yarn.

Then, three yarns spun from polyethylene terephthalate fibers (trade name: P902F 830T/72F, manufactured by TEIJIN LIMITED) (total fineness: 830 dtex, total densities of three: 830 × 3 = 2490 dtex) were prepared. As a sheath yarn, the sheath yarn was wound so as to cover the spun core yarn, and the core yarn and the sheath yarn were twisted at 47 times/m in the Z direction, and the crepe yarn of the core sheath structure was spun.

<Measurement of tensile strength of crepe>

A yarn of a predetermined length (ensuring an effective length of 20 cm) was cut out from the spun yarn and used as a yarn sample, and a tensile load measuring machine (A&D Company, Limited, manufactured by A&D Company, Limited) was used in accordance with JIS L1013. RTG1310), the tensile strength [N] of the crepe 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 core yarn was spun in the same manner as in the above-described first embodiment except that the core yarn was spun at 217 times/m in the S direction and the core yarn and the sheath yarn were integrally twisted at 217 times/m in the Z direction. The crepe of the sheath structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Example 3)

The core was spun in the same manner as in the above-described first embodiment except that the core yarn was spun at 136 times/m in the S direction and the core yarn and the sheath yarn were integrally twisted at 62 times/m in the Z direction. The crepe of the sheath structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Example 4)

The core yarn was spun in the same manner as in the above-described first embodiment except that the core yarn was spun at 340 rpm in the S direction and the core yarn and the sheath yarn were integrally twisted at 217 rpm in the Z direction. The crepe of the sheath structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Example 5)

The core was spun in the same manner as in the above-described first embodiment except that the core yarn was spun at 364 times/m in the S direction and the core yarn and the sheath yarn were integrally twisted at 217 times/m in the Z direction. The crepe of the sheath structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Example 6)

First, three yarns obtained by spinning a polyarylate fiber (manufactured by Kuraray Co., Ltd., trade name: Vectran (registered trademark)) formed of a molten liquid crystal polymer (total fineness: 1670 dtex, three total fineness: 1670 × 3 = 5010 dtex)), twisted at 46 rpm in the S direction, and spun the core yarn.

Then, six yarns spun from polyethylene terephthalate fibers (trade name: P902F 830T/72F, manufactured by TEIJIN LIMITED) were prepared (total fineness: 830 dtex, total fineness of 6: 830 × 6 = 4980 dtex) As a sheath yarn, the sheath yarn was wound so as to cover the spun core yarn, and the core yarn and the sheath yarn were twisted in the Z direction at 116 times/m to spun the core yarn structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Example 7)

First, three yarns spun from a para-aramid fiber (manufactured by DuPont, trade name: Kevlar 29) (total fineness: 1670 tex, 3 total fineness: 1670 × 3 = 5010 dtex) were prepared, and 46 times in the S direction. /m twisted, spun core yarn.

Then, six yarns spun from polyethylene terephthalate fibers (trade name: P902F 830T/72F, manufactured by TEIJIN LIMITED) were prepared (total fineness: 830 dtex, total fineness of 6: 830 × 6 = 4980 dtex) As a sheath yarn, the sheath yarn was wound so as to cover the spun core yarn, and the core yarn and the sheath yarn were twisted in the Z direction at 116 times/m to spun the core yarn structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Example 8)

First, a yarn (total fineness: 1760 dtex) spun from ultrahigh molecular weight polyethylene fiber (trade name: Dyneema, manufactured by TOYOBO CO., LTD.) was prepared, and twisted at 90 rpm in the S direction, and spun. Core yarn.

Then, three yarns spun from polyethylene terephthalate fibers (trade name: P902F 830T/72F, manufactured by TEIJIN LIMITED) (total fineness: 830 dtex, total densities of three: 830 × 3 = 2490 dtex) were prepared. As a sheath yarn, the sheath yarn was wound so as to cover the spun core yarn, and the core yarn and the sheath yarn were twisted at 90 times/m in the Z direction to spun the core yarn structure.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Comparative Example 1)

One of the yarns (total fineness: 1670 dtex) spun by a polyarylate fiber (manufactured by Kuraray Co., Ltd., trade name: Vectran (registered trademark)) formed of a molten liquid crystal polymer was prepared, and 74 times in the S direction. /m twisted and spun yarn.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Comparative Example 2)

First, one is prepared from a polyarylate fiber formed of a molten liquid crystal polymer (manufactured by Kuraray Co., Ltd., trade name: Vectran (registered trademark) spun yarn (total fineness: 1670 dtex), twisted at 420 rpm in the S direction, and spun yarn was spun.

Then, three yarns spun from polyethylene terephthalate fibers (trade name: P902F 830T/72F, manufactured by TEIJIN LIMITED) (total fineness: 830 dtex, total densities of three: 830 × 3 = 2490 dtex) were prepared. As a sheath yarn, the sheath yarn was wound so as to cover the spun core yarn, and the core yarn and the sheath yarn were twisted at 248 times/m in the Z direction, and the crepe yarn of the core sheath structure was spun.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Comparative Example 3)

First, three yarns obtained by spinning a polyarylate fiber (manufactured by Kuraray Co., Ltd., trade name: Vectran (registered trademark)) formed of a molten liquid crystal polymer (total fineness: 1670 dtex, three total fineness: 1670×3=5010dtex)), twisted at 81 times/m in the S direction, and spun yarn was spun.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Comparative Example 4)

First, three yarns spun from a para-aramid fiber (manufactured by DuPont, trade name: Kevlar 29) (total fineness: 1670 tex, 3 total fineness: 1670 × 3 = 5010 dtex) were prepared, and 81 times in the S direction. /m twisted and spun yarn.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

(Comparative Example 5)

First, a yarn (total fineness: 1760 dtex) spun from ultrahigh molecular weight polyethylene fiber (trade name: Dyneema, manufactured by TOYOBO CO., LTD.) was prepared, and twisted at 80 rpm in the S direction, and spun. Out of the crepe.

Further, the tensile strength of the crepe was measured in the same manner as in the above Example 1. The above results are shown in Table 5.

table 5

As can be seen from Table 5, the tensile strength of the crepe of Examples 1 to 5 in which the net core twist coefficient K is in the range of 0 to 60 is higher than that of the crepe yarn of Comparative Example 1 (the twist is 74 times), and the strength is improved. . Among them, the crepe of Comparative Example 1 was spun only from the polyarylate fibers formed of the molten liquid crystal polymer spun into the core yarns of Examples 1 to 5.

The strength utilization ratio of each of the crepe yarns in Examples 1 to 5 (that is, (the tensile strength of any of the crepe yarns of Examples 1 to 5 and the tensile strength of the crepe of Comparative Example 1) × 100) More than 100%.

It is also known that the twisting strength of the crepe of Example 6 is improved and the strength is improved as compared with the crepe yarn of Comparative Example 3 (the twist is 81 times). Here, the crepe of Comparative Example 3 was spun only from the polyarylate fiber formed of the molten liquid crystal polymer spun into the core yarn of Example 6. It is also known that the strength utilization ratio of the crepe of Example 6 (that is, (the tensile strength of the crepe of Example 6 / the tensile strength of the crepe of Comparative Example 3) × 100) was more than 100%.

It was also found that the twisting strength of the crepe of Example 7 was higher than that of Comparative Example 4 (the twist was 81 times), and the strength was improved. Here, the crepe of Comparative Example 4 was spun only from the para-type aramid fiber spun into the core yarn of Example 7. It is also understood that the strength utilization ratio of the crepe of Example 7 (that is, (the tensile strength of the crepe of Example 7 / the tensile strength of the crepe of Comparative Example 4) × 100) was more than 100%.

It is also understood that the twisting strength of the crepe of Example 8 is improved and the strength is improved as compared with the crepe yarn of Comparative Example 5 (the twist is 80 times). Here, the crepe of Comparative Example 5 was spun only from the ultrahigh molecular weight polyethylene fiber spun into the core yarn of Example 8. It is also understood that the strength utilization ratio of the crepe of Example 8 (that is, (the tensile strength of the crepe of Example 8 / the tensile strength of the crepe of Comparative Example 5) × 100) was more than 100%.

Further, since the net yarn defect coefficient K of the crepe of Comparative Example 2 was more than 60, the crepe of Comparative Example 2 was inferior in strength and strength utilization as compared with the crepe yarn of Comparative Example 1 (the twist was 74 times). Here, the crepe of Comparative Example 1 was spun only from the polyarylate fiber formed of the molten liquid crystal polymer spun into the core yarn of Comparative Example 2.

Industrial availability

In summary, the present invention is applicable to a yarn composed of a core yarn and a sheath yarn and used for manufacturing a twisted yarn such as a rope.

Claims (5)

A crepe yarn comprising a core yarn composed of a fiber having a strength of 15 cN/dtex or more and a sheath yarn composed of a thermoplastic fiber or a natural fiber and coated with a core yarn, characterized by the following formula (1) The calculated net core twist factor K is 0~60, K=T/(10,000/D) ^1/2 (1) where D is the total fineness of the core yarn, the unit is dtex, and T is (wound The absolute value of the core yarn before the sheath yarn) (the twist after the core yarn and the sheath yarn have been wound) (back/m). The crepe of claim 1, wherein the core yarn is covered by a plurality of the aforementioned sheath yarns. The crepe of claim 1 or 2, wherein the fiber is derived from a polyarylate fiber, aramid fiber, polyethylene fiber, polyparaphenylene benzoxazole fiber, carbon fiber, and glass fiber formed of a molten liquid crystal polymer. At least one selected from the group consisting of. The crepe according to any one of claims 1 to 3, wherein the thermoplastic fiber is selected from the group consisting of polyester fiber, nylon fiber, polyethylene fiber, polypropylene fiber, polyvinyl alcohol fiber, and vinylidene fiber. At least one of the above-mentioned natural fibers is at least one selected from the group consisting of cotton, wool, silk, and hemp. A crepe structure made of the crepe of any one of claims 1 to 4.