JP7176413B2 - High tenacity fine polyester multifilament - Google Patents

Description

The present invention relates to a high-strength, fine-denier multifilament that is excellent in weavability and abrasion resistance, and that can be used in high-density thin fabrics that are particularly suitable for sports and outdoor clothing applications.

Many proposals have been made for high-density fabrics using synthetic fiber multifilament, such as polyester and nylon, mainly for applications such as sportswear and airbags. There is a demand for woven fabrics that are thinner and, accordingly, have higher strength. Particularly in sports and outdoor clothing, there is an increasing demand for improved durability against strenuous movement, and improved abrasion resistance of textiles is demanded.

In Patent Document 1, the intrinsic viscosity of polyethylene terephthalate is set to 0.70 to 1.20 to increase the strength, and 60% or more of the total number of titanium oxide particles has a primary particle diameter of 0.1 to 0.6 μm. A single-component polyester multifilament fabric having improved weaving properties by containing 0.3 to 0.8% by weight (wt) of is proposed.

In order to make the fabric thinner, it is necessary to reduce the total fineness of the yarn, which inevitably reduces the number of filaments that make up the yarn. . If the convergence is poor, the process passability of the manufacturing process is deteriorated, and the handling during warping and weaving becomes difficult. In addition, since the convergence is insufficient, filament splitting (single yarn separation) occurs, and the handling of warp yarns during weaving becomes poor, and warp yarn breakage is likely to occur. Warp breakage not only causes the machine to stop, but also requires a great deal of labor to reconnect and restore the warp yarns, resulting in a significant drop in productivity. Also, filament cracking causes streak-like defects in fabric quality. In Patent Document 2, in order to provide a polyamide multifilament with excellent convergence, despite the fineness of the total fineness of 6 to 18 dtex, the single filament fineness is made finer to 0.8 dtex or less to facilitate entanglement. It is proposed that the degree of entanglement should be 25 or more.

In Patent Document 3, the core-sheath type composite yarn is used as the monofilament, and the intrinsic viscosity of the polyester used as the core component is set to 0.70 or more to increase the strength, and the intrinsic viscosity of the polyester used as the sheath component is set to 0.70% lower than that of the core component. A polyester monofilament for screen gauze is proposed in which scum is suppressed (abrasion resistance is improved) by lowering it by 15 to 0.30.

JP 2009-074213 (paragraph number [0008] to [0009]) JP 2009-013511 (paragraph number [0008] to [0009]) JP 2003-213528 (paragraph number [0013] to [0014])

However, the single-component polyester of Patent Document 1 has a problem with wear resistance and cannot meet the durability requirements for advanced applications.

In Patent Document 2, it is true that weaving performance is greatly improved by increasing the degree of entanglement and convergence. .

In Patent Document 3, the monofilament is difficult to form into a high-density fabric, and the high single filament fineness increases the rigidity of the fabric, making it unsuitable for clothing applications. In addition, when the core-sheath type composite yarn technology is applied to fine multifilament, if the single filament fineness of the core-sheath type composite yarn is reduced, the sheath will crack and the sheath will become too thin, resulting in insufficient abrasion resistance. The problem was that it was not possible to obtain On the other hand, when the single yarn fineness is increased, the number of filaments is decreased, so entanglement is difficult to occur, convergence is deteriorated, and weaving performance and fabric quality are deteriorated.

In other words, with conventional technology, it is difficult to obtain polyester multifilament for thin fabrics that has the durability, weaving properties, and fabric quality required for advanced applications. The development of polyester multifilament with fineness is expected.

The present invention solves the problems of the prior art, and provides a high-strength and excellent high-strength thin fabric suitable for sports and outdoor clothing applications that has excellent durability, weaveability, and fabric quality. To provide a fine polyester multifilament with excellent abrasion resistance and convergence.

The object of the present invention can be achieved by providing the following polyester multifilament.

A polyester multifilament in which a plurality of single yarns in which a high-viscosity polyester core component and a low-viscosity polyester sheath component are combined in a core-sheath type are bundled, and the intrinsic viscosity difference between the core component and the sheath component is 0.20 to 1. 00, total fineness 4-30 dtex, single filament fineness 1.0-5.0 dtex, breaking strength 5.0-9.0 cN/dtex, breaking elongation 12-45%, entanglement degree 2.0-15. It is a polyester multifilament characterized by having 0 pieces/m and having 3 to 15 filaments.

Further, the polyester multifilament is characterized in that the high-viscosity polyester core component has an intrinsic viscosity of 0.70 to 1.50, and the low-viscosity polyester sheath component has an intrinsic viscosity of 0.40 to 0.70.

The polyester multifilament of the present invention has high tenacity, excellent wear resistance and convergence, and provides a high-density thin fabric suitable for sports and outdoor clothing applications, which has excellent durability, weavability, and fabric quality. be able to.

The polyester multifilament of the present invention will be explained.

The polyester multifilament of the present invention comprises core-sheath type conjugate fibers arranged such that the core component is covered with the sheath component in the cross section of the single yarn and the core component is not exposed on the surface. In general, in order to increase the strength of polyester fiber, it is known that it should be drawn at a high draw ratio in the manufacturing process of the raw yarn to achieve high orientation and high crystallinity. In weaving, since the total fineness is small and the warp is woven at a high density, the warp receives a large amount of rubbing from the reed under a strong load, and there is a problem that fluff is generated due to single yarn breakage. In addition, thin woven fabrics used for sophisticated applications are required to have durability against friction, and improvement of the abrasion resistance of raw yarn is an important issue.

In the polyester multifilament of the present invention, from the viewpoint of obtaining excellent wear resistance, the intrinsic viscosity of the polyester used for the sheath component must be lower than the intrinsic viscosity of the polyester core component, and the difference between them must be 0.20 to 1.00. It is preferable to By setting the difference in intrinsic viscosity to 0.20 or more, it is possible to suppress the degree of orientation and degree of crystallinity of the fiber surface of the polyester of the sheath component, that is, the polyester multifilament, and to obtain good abrasion resistance. In addition, since the sheath component bears the shearing stress on the inner wall surface of the spinneret discharge hole of melt spinning, the shearing force that the core component receives is reduced, and the core component has a low degree of molecular chain orientation and is spun in a uniform state. The strength of the finally obtained polyester multifilament is improved. On the other hand, in order for the polyester multifilament to have high strength, the orientation of the sheath component is also required to be moderate. More preferably, the difference in intrinsic viscosity of the polyester is from 0.30 to 0.70.

The intrinsic viscosity of the high-viscosity polyester core component used in the polyester multifilament of the present invention is preferably in the range of 0.70 to 1.50. By setting the intrinsic viscosity to 0.70 or more, it becomes possible to produce a polyester multifilament having both sufficient strength and elongation. A more preferable intrinsic viscosity is 0.80 or more. In addition, the upper limit of the intrinsic viscosity is preferably 1.50 or less from the viewpoint of ease of molding such as melt extrusion, further reducing the molecular weight due to molecular chain scission caused by heat and shear force in the manufacturing process and the manufacturing cost, and stabilizing the melt flow. Considering the nature, it is more preferably 1.20 or less.

On the other hand, by setting the intrinsic viscosity of the low-viscosity polyester of the sheath component to 0.40 or more, stable spinning properties can be obtained. A more preferable intrinsic viscosity is 0.50 or more. Moreover, in order to obtain good wear resistance, it is preferably 0.70 or less.

As the polyester of the polyester multifilament of the present invention, polyester containing polyethylene terephthalate (hereinafter referred to as PET) as a main component is used.

As the PET used in the present invention, a polyester containing terephthalic acid as a main acid component and ethylene glycol as a main glycol component and having 90 mol % or more of repeating units of ethylene terephthalate can be used. However, it may contain other copolymer components capable of forming an ester bond at a ratio of less than 10 mol %. Such copolymer components include, for example, acidic components such as isophthalic acid, phthalic acid, dibromoterephthalic acid, naphthalenedicarboxylic acid, bifunctional aromatic carboxylic acids such as octoethoxybenzoic acid, sebacic acid, oxalic acid, Bifunctional aliphatic carboxylic acids such as adipic acid and dymic acid, and dicarboxylic acids such as cyclohexanedicarboxylic acid, and glycol components such as ethylene glycol, diethylene glycol, propanediol, butanediol, neopentyl Glycols, bisphenol A, cyclohexanedimethanol, and polyoxyalkylene glycols such as polyethylene glycol and polypropylene glycol may be mentioned, but are not limited to these.

In addition, titanium dioxide as a matting agent, fine particles of silica and alumina as a lubricant, hindered phenol derivatives as an antioxidant, flame retardants, antistatic agents, ultraviolet absorbers and coloring pigments are added to PET as necessary. can do.

In addition, since the core component PET is mainly responsible for the strength of the polyester multifilament, it is preferable that the amount of the additive of inorganic particles typified by titanium oxide, which is usually added to polyester fibers, is 0.5 wt % or less. On the other hand, since the sheath component PET is mainly responsible for the wear resistance of the polyester multifilament, it is preferable to add about 0.1 wt % to 0.5 wt % of inorganic particles represented by titanium oxide.

Next, the cross-sectional shape of the polyester multifilament of the present invention will be described.

As described above, the polyester multifilament of the present invention is a core-sheath type composite polyester multifilament in which the core component is covered with the sheath component in the cross section of the single yarn and the core component is not exposed on the surface. filament. Here, the core-sheath type means that the core component is completely covered with the sheath component, and does not necessarily need to be arranged concentrically. Regarding the cross-sectional shape, there are many shapes such as round, flat, triangular, square, and pentagonal. is preferred.

In the present invention, since both the core component and the sheath component are polyester, the phenomenon of peeling at the composite interface, which frequently occurs in polyester/nylon composite yarns, is less likely to occur. However, in order to achieve both the wear resistance improvement effect of the sheath component and the strength enhancement of the core component, the composite ratio of the core component:the sheath component is preferably in the range of 60:40 to 95:5, and is more preferable. The ratio ranges from 70:30 to 90:10.

Here, the composite ratio defined in the present invention is the cross-sectional area ratio of two kinds of polyesters constituting a single yarn in a cross-sectional photograph of a polyester multifilament single yarn.

The polyester multifilament of the present invention must have a total fineness of 4 to 30 dtex. When the density is 4 dtex or more, stable spinning and weaving are possible. A preferred total fineness range is 8 to 25 dtex.

Further, the polyester multifilament of the present invention must have a single filament fineness of 1.0 to 5.0 dtex. If the single filament fineness is less than 1.0 dtex, it becomes difficult to form the desired core-sheath cross section, which tends to cause sheath cracking, reduce the thickness of the sheath component, and result in insufficient abrasion resistance. In addition, there is a tendency for process passability such as spinning property and weaving property to deteriorate. In addition, by making it 5.0 dtex or less, it becomes easy to impart entanglement, convergence is improved, and the effect of improving process passability and weaving property is obtained. In addition, the resulting woven fabric maintains its denseness, does not become too hard, and has a good feel. A preferable single yarn fineness range is 1.5 to 3.0 dtex. In order to achieve the single filament fineness as described above, the discharge rate and the spinneret may be appropriately changed in the polyester multifilament production method.

Furthermore, the polyester multifilament of the present invention must have 3 to 15 filaments. By setting the number of filaments to 3 or more, entanglement is likely to occur. In addition, when the number of filaments increases, the contact with reeds and guides during weaving can be distributed to each single yarn, so the friction load applied to the single yarn can be reduced, and the abrasion resistance of the raw yarn and the durability of the fabric can be improved. significantly improve performance. The upper limit of the number of filaments is 15 or less, depending on the total fineness and single filament fineness.

The polyester multifilament of the present invention should have increased convergence in order to obtain excellent weavability and fabric quality. If the convergence is insufficient, filament splitting (single yarn separation) occurs, and warp handling becomes poor during weaving, and warp breakage is likely to occur. In terms of fabric quality, filament cracking causes streak-like fabric defects.

The polyester multifilament of the present invention needs to have a degree of entanglement representing the number of entanglements per m of 2.0 to 15.0/m. If the degree of entanglement is less than 2.0 pieces/m, there is a tendency that weaving properties such as warp breakage deteriorate. The obtained fabric has streak-like fabric defects due to filament splitting, and tends to be inferior in fabric quality. When the degree of entanglement is 2.0 pieces/m or more, excellent weavability and fabric quality can be obtained. On the other hand, if the degree of entanglement is too high, there will be too many restraint points, and the above-mentioned contact with the reed, guide, etc. during weaving will be distributed to each single yarn, and the frictional load applied to the single yarn will be reduced. The effect of entanglement is reduced, and the wear resistance of the raw yarn and the durability of the woven fabric tend to be inferior. Furthermore, in order to increase the degree of entanglement, the load in the entanglement process is increased, and yarn breakage often occurs, which may deteriorate productivity. A more preferable range of entanglement degree is 4.0 to 10.0 pieces/m.

The polyester multifilament of the present invention has a breaking strength of 5.0 cN/dtex or more, so that sufficient mechanical properties can be obtained even as a thin woven fabric. More preferably, it is 6.0 cN/dtex or more. Also, from the viewpoint of abrasion resistance, it is necessary to suppress orientation and crystallinity, so it is 9.0 cN/dtex or less, more preferably 8.0 cN/dtex or less.

In addition, the polyester multifilament of the present invention has a breaking elongation of 12% or more, so that it can suppress yarn breakage and fluffing during weaving, and is excellent in handleability. Target breaking strength is obtained. A more preferable breaking elongation range is 17 to 35%.

Furthermore, the strength at 5% elongation (5% Mo) and the strength at 10% elongation (10% Mo) of the polyester multifilament of the present invention are 3.5 cN at 5% Mo from the viewpoint of the dimensional stability of the fabric. /dtex or more is preferable, and 3.8 cN/dtex or more is more preferable. 10% Mo is preferably 4.0 cN/dtex or more, more preferably 4.5 cN/dtex or more. In addition, 5% Mo is preferably 6.0 cN/dtex or less, more preferably 5.0 cN/dtex or less, in order to suppress orientation and crystallinity from the viewpoint of wear resistance. 10% Mo is preferably 8.0 cN/dtex or less, more preferably 7.0 cN/dtex or less.

Next, a preferred method for producing the polyester multifilament of the present invention will be described.

A feature of the method for producing the polyester multifilament of the present invention is that the entanglement is performed after the drawing. When entangling is imparted at the undrawn yarn stage, it is difficult to entangle within the ranges of the total fineness, single filament fineness, and filament number of the multifilament of the present invention. Therefore, it is possible to achieve the desired degree of entanglement by applying entanglement at the stage when the single yarn fineness after drawing becomes small.

A known entangling nozzle can be used in the method for imparting entanglement to the polyester multifilament of the present invention. The pneumatic pressure for entangling is preferably 0.10 to 0.40 MPa. If the tension is less than 0.10 MPa, it is difficult to achieve sufficient entanglement. More preferably, it is 0.15 to 0.30 MPa.

The method for spinning the polyester multifilament of the present invention is not particularly limited, and can be based on known techniques. For example, high-viscosity PET as a core component and low-viscosity PET as a sheath component are respectively melt extruded, sent to a predetermined composite pack using a composite spinning machine, both polymers are filtered in the pack, and then the core and sheath are passed through a spinneret. The fibers are bonded to a mold and subjected to conjugate spinning, and the yarn ejected from the spinneret is taken off to obtain an undrawn yarn. This undrawn yarn may be wound once and then drawn by a drawing machine, or may be a one-step method in which drawing is continued without once winding the undrawn yarn. The two-step method is more preferable because entanglement becomes difficult to occur when the yarn speed is high.

The method for drawing the polyester multifilament of the present invention is not particularly limited, and can be based on known techniques. For example, a method of heating and drawing in one stage between the first hot roll and the second hot roll, a method of heating and drawing in one stage with the first hot roll and unheated rolls, and a hot plate between the rolls, and the first hot roll and The method can be preferably selected from a method of performing the first-stage heat drawing between the second hot rolls, a method of performing the second-stage heat drawing between the second hot rolls and the third hot rolls, and the like. In order to achieve a particularly high strength, it is necessary to draw the undrawn yarn at a high magnification. It is preferable to draw the film in two or more steps because problems such as sagging occur.

In the case of one-stage drawing, the temperature for drawing the polyester multifilament of the present invention is usually the glass transition temperature of the high-viscosity PET core component + 10 to 30 ° C. with the first hot roll, and the second hot roll or hot roll. The plate is preferably in the range of 130-230°C. By setting the temperature to 130° C. or higher, the orientation is controlled, the crystallization of the fiber is promoted, and the strength is increased. On the other hand, when the temperature is 230° C. or lower, the fusion on the hot roll or hot plate is prevented, and the spinning property is improved. In the case of multi-stage stretching, the first hot roll is set to the glass transition temperature of the high-viscosity PET core component +10 to 30° C., and the temperature of the second and subsequent hot rolls is preferably gradually increased. A temperature range of 100 to 230° C. is preferred.

Furthermore, the draw ratio of the polyester multifilament of the present invention is preferably 3.0 to 7.0 times in total. More preferably 3.5 to 6.0 times, still more preferably 3.8 to 5.0 times.

Hereinafter, the polyester multifilament of the present invention will be specifically described with reference to examples. The measured values in the examples were measured by the following methods.

(1) Intrinsic viscosity (IV)
Relative viscosity defined by η/η ₀ : ηr is obtained by dissolving 0.8 g of a sample polymer in 10 mL of o-chlorophenol (hereinafter abbreviated as OCP) having a purity of 98% or more at a temperature of 25° C. to obtain a polymer solution. It was obtained from the following formula using an Ostwald viscometer at a temperature of 25°C. From ηr, the intrinsic viscosity (IV) was calculated from the following formula.
ηr=η/η ₀ =(t×d)/(t ₀ ×d ₀ )
Intrinsic viscosity (IV) = 0.0242ηr + 0.2634
Here, η: viscosity of polymer solution η ₀ : viscosity of OCP t: drop time of solution (seconds) d: density of solution (g/cm ³ ) t ₀ : drop time of OCP (seconds) d ₀ : OCP Density (g/cm ³ ).

(2) Total fineness (dtex)
A skein of 500 m of yarn was taken, and the value obtained by multiplying the mass (g) of the skein by 20 was taken as the fineness.

(3) Breaking strength (cN/dtex) and breaking elongation (%), strength (modulus) at 5% elongation (cN/dtex) and strength (modulus) at 10% elongation (cN/dtex)
It was measured using Orientec Tensilon UCT-100 according to JIS L1013 (1999).

(4) Degree of entanglement (pieces/m)
The yarn was floated on water, and the number of convergence points per 1 m was measured to obtain the degree of entanglement. The measurement was performed 10 times and the average value was calculated.

(5) Abrasion resistance of raw yarn A yarn tension of 0.9 g/dtex is applied to the yarn, and the flat part of the reed (material: SK material, width 7 mm × length 50 mm × thickness 50 μm) is adjusted so that the contact angle is 20°. and reciprocated at a stroke length of 30 mm and a speed of 670 times/min for 10 minutes. The yarn after the treatment was observed under an enlarged microscope, and A was given when no fluff or fibrillation (surface scraping) was observed, and C was given when observed.

(6) Evaluation of Weaving Performance and Weaving Quality Weaving was carried out with a water jet loom so that the basis weight was in the range of 30 to 35 g/m ² by adjusting the total fineness of the filaments used. The weaving performance was evaluated as S when the number of times the fabric stopped due to yarn breakage or the like per 100 m was less than 3 times, A when 3 times or more and less than 10 times, and C when 10 times or more. The weaving quality counted the total number of defects such as fuzz and filament cracks, and was evaluated as S when less than 3 per 100 m, A when 3 or more and less than 10, and C when 10 or more.

(7) Fabric Abrasion Resistance Fabric abrasion resistance was measured according to E method (Martindale method) according to JIS L1096 (2010). As for the test conditions, a standard friction cloth made of polyester was used, and the pressing load was 9 kPa. The evaluation was based on the number of times of abrasion until fluff was generated.

Regarding the production methods of Examples and Comparative Examples, polyester filaments were obtained according to known techniques under the production conditions shown in Tables 1 to 3.

[Example 1]
PET with an intrinsic viscosity of 0.80 as a core component and PET with an intrinsic viscosity of 0.50 as a sheath component are melted at a temperature of 295 ° C. using an extruder type extruder, and the polymer temperature is 290 ° C. The composite ratio is the core component. : Sheath component = 80:20 was measured by the pump and flowed into a known composite spinneret having 5 holes to form a core-sheath type. The yarn extruded from the spinneret is once wound at a spinning speed of 1,200 m/min, and then passed through a first hot roll heated to 90°C and a second hot roll heated to 130°C in a known drawing device. It was stretched between rolls at a draw ratio of 4.2 times and heat set. The obtained drawn yarn was entangled at an entangling pressure of 0.23 MPa by an entangling nozzle installed between the final roll and the winding machine, and then wound at 800 m/min. There is no particular problem with the spinnability, and a polyester multifilament with a total fineness of 12.0 dtex, a single filament fineness of 2.4 dtex, a breaking strength of 6.5 cN/dtex, a breaking elongation of 17.7%, and a degree of entanglement of 5.8 pieces/m is used. Obtained. The yarn abrasion resistance of this polyester multifilament was good. Other raw yarn physical properties were as shown in Table 1.

Using this polyester multifilament, weaving was performed with a water jet loom so that the basis weight was 30 g/m ² . There was no yarn breakage in the weaving of 100m, and the weaving performance was very good. The resulting fabric had no defects such as fluff and was of very good weaving quality. The abrasion resistance of the fabric was good, with no fluff even after 6,000 abrasions.

[Examples 2-3]
Polyester multifilaments were obtained in the same manner as in Example 1, except that the draw ratios were 3.9 times and 3.6 times, respectively. The physical properties of the obtained polyester multifilament yarn were as shown in Table 1. In both Examples 2 and 3, there was no thread breakage in the weaving of 100 m, and the weavability was very good. The resulting fabric had no defects such as fluff and was of very good weaving quality. The abrasion resistance of the fabric was good, with no fluff even after 6,000 abrasions.

[Examples 4-5], [Comparative Examples 1-2]
A polyester multifilament was obtained in the same manner as in Example 1, except that the entangling pressure was changed in the range of 0.08 to 0.42 MPa. The physical properties of the obtained polyester multifilament yarn were as shown in Table 1. In Example 4, the degree of entanglement was 9.9 pieces/m, and good results similar to those in Example 1 were obtained in terms of yarn abrasion resistance, weaving performance, weaving quality, and fabric abrasion resistance. In Example 5, the degree of entanglement was 4.2 pieces/m, and convergence was slightly inferior to that in Example 1. Therefore, yarn breakage occurred 3 times in the weaving of 100 m, but the weaving performance was good. Although the resulting fabric had no fluff, it had the defect of filament cracking and was slightly inferior to that of Example 1. In Comparative Example 1, the entangling pressure was high, the yarn swayed at the entangling position, and yarn breakage occurred. The degree of entanglement was as high as 15.3 pieces/m, and the abrasion resistance of the raw yarn was inferior to that of Example 1 because fluff was easily generated. Yarn breakage occurred 6 times during weaving, and the weaving quality was inferior to that of Example 1 with fluff. As for the abrasion resistance of the fabric, fluff was generated even after 3,500 abrasions. In Comparative Example 2, the entangling pressure was low, the entangling degree was 1.7 pieces/m, and the entangling could not be sufficiently introduced. During weaving, warp breakage occurred frequently, and machine stops occurred every several meters. As for the weaving quality, there were many filament cracks and many streak-like defects were observed.

[Comparative Example 3]
A polyester multifilament was obtained in the same manner as in Example 1, except that the entanglement position was set before winding the yarn. The physical properties of the obtained polyester multifilament yarn were as shown in Table 2. The degree of entanglement was 0.8 pieces/m, and the entanglement was not sufficient. During weaving, warp breakage occurred frequently, and machine stops occurred every several meters. As for the weaving quality, there were many filament cracks and many streak-like defects were observed.

[Examples 6-8], [Comparative Examples 4-5]
A polyester multifilament was obtained in the same manner as in Example 2, except that the discharge rate and the number of holes in the spinneret were adjusted, and the total fineness, the single filament fineness, and the number of filaments were changed. The physical properties of the obtained polyester multifilament yarn were as shown in Table 2. Examples 6 to 8 had the same raw yarn physical properties, weaving properties, weaving quality, and fabric abrasion resistance as those of Example 2. In Comparative Example 4, the single filament fineness was as large as 5.6 dtex, so the degree of entanglement was 1.2 pieces/m, and entanglement could not be achieved sufficiently. During weaving, warp breakage occurred frequently, and machine stops occurred every several meters. As for the weaving quality, there were many filament cracks and many streak-like defects were observed. Further, the resulting fabric had a stiff texture. In Comparative Example 5, there were many single yarn breakages during spinning, and many single yarn windings occurred during drawing. Since the obtained polyester multifilament had a small single filament fineness of 0.8 dtex, the degree of entanglement was as high as 18.8 pieces/m. The polyester multifilament after the yarn abrasion test had a lot of fluff and was inferior in abrasion resistance. Moreover, when the obtained polyester multifilament was woven, the warp broke frequently, and the weaving could not be performed at all.

[Comparative Example 6]
A polyester monofilament was obtained in the same manner as in Example 1, except that the number of holes in the spinneret was changed to 1 and the discharge rate was changed, and the entangling nozzle was not used. The physical properties of the obtained polyester monofilament were as shown in Table 2. The resulting polyester monofilament could not be woven at all because of frequent breakage of both the warp and the weft on a water jet loom.

[Example 9]
Spinning was carried out in the same manner as in Example 1, except that PET having an intrinsic viscosity of 1.00 was used as the core component and the spinning speed was 600 m/min. After being wound once, it is stretched in two stages at a draw ratio of 4.5 times between the first and second hot rolls heated to 90°C and the third hot roll heated to 200°C in a known stretching device. Then, the polyester multifilament was obtained by stretching in the same manner as in Example 1 except that heat setting was performed. The physical properties of the obtained polyester multifilament yarn were as shown in Table 3. In the weaving, there was no yarn breakage at 100 m, and the weaving performance was very good. The resulting fabric had no defects such as fluff and was of very good weaving quality. The abrasion resistance of the fabric was good, with no fluff even after 6,000 abrasions.

[Example 10]
A polyester multifilament was obtained in the same manner as in Example 9, except that PET having an intrinsic viscosity of 1.25 was used as the core component, the spinning speed was 500 m/min, and the draw ratio was 5.8 times. The physical properties of the obtained polyester multifilament yarn were as shown in Table 3. As for the abrasion resistance of the raw yarn, fluff and fibrillation were not observed, but warp breakage occurred 8 times in the weaving of 100m. The quality of the obtained fabric was inferior to that of Example 1 because fluff was observed. The abrasion resistance of the fabric was inferior to that of Example 1, with fluff occurring after 4,500 abrasions.

[Comparative Example 7]
PET having an intrinsic viscosity of 0.80 was used as a single component, melted at a temperature of 295°C using an extruder type extruder, and then flowed into a known single component die having 5 holes at a polymer temperature of 290°C. The yarn extruded from the spinneret is temporarily wound at a spinning speed of 800 m/min, and then passed between a first hot roll heated to 90°C and a second hot roll heated to 130°C by a known drawing device. The film was stretched at a draw ratio of 4.3 times and heat set. The obtained drawn yarn was entangled at an entangling pressure of 0.23 MPa by an entangling nozzle installed between the final roll and the winding machine, and then wound at 800 m/min. The physical properties of the obtained polyester multifilament yarn were as shown in Table 3. The abrasion resistance of the yarn was inferior to that of Example 1 because fluff was easily generated. There was no thread breakage in the weaving of 100 m, and the weaving performance was very good. As for the abrasion resistance of the fabric, fluffing was observed after 500 abrasions, and the abrasion resistance was greatly inferior to that of Example 1.

[Example 11]
Using PET with an intrinsic viscosity of 0.80 as a core component and PET with an intrinsic viscosity of 0.50 as a sheath component, spinning and drawing were performed with a known direct spinning and drawing apparatus. After melting at a temperature of 295°C using an extruder-type extruder, the polymer is pumped at a temperature of 290°C and metered so that the composite ratio is core component:sheath component = 80:20, so as to form a core-sheath type. It was made to flow into a known composite spinneret with 5 holes. The yarn extruded from the spinneret was taken up at a spinning speed of 1,300 m/min, stretched at a draw ratio of 3.8 times without being wound once, and heat-set. The obtained drawn yarn was entangled at an entangling pressure of 0.23 MPa by an entangling nozzle installed between the final roll and the winder, and then wound at 5,000 m/min. Yarn breakage was observed at the entangled portion, and the result was inferior to that of the two-step method as in Example 1. The physical properties of the obtained polyester multifilament yarn were as shown in Table 3. The single yarn fineness at the entangling position after stretching is 2.4 dtex, which is equivalent to Example 1, but the speed when passing through the entangling nozzle is as high as 5,000 m / The frequency became as small as 2.8 pieces/m. Since the degree of entanglement was inferior to that of Example 1, convergence was poor, and yarn breakage occurred 7 times during weaving of 100m. Although the resulting fabric had no fluff, it had the defect of filament cracking and was slightly inferior to that of Example 1.

[Comparative Example 8]
A polyester multifilament was obtained in the same manner as in Example 11, except that the entanglement position was set before take-off of the spinning. The physical properties of the obtained polyester multifilament yarn were as shown in Table 3. The degree of entanglement was 0.7 pieces/m, and the entanglement could not be sufficiently included. During weaving, warp breakage occurred frequently, and machine stops occurred every several meters. As for the weaving quality, there were many filament cracks and many streak-like defects were observed.

Claims (2)

A polyester multifilament in which a plurality of single yarns in which a high-viscosity polyester core component and a low-viscosity polyester sheath component are combined in a core-sheath type are bundled, and the intrinsic viscosity difference between the core component and the sheath component is 0.20 to 1. 00, total fineness 4-30 dtex, single filament fineness 1.0-5.0 dtex, breaking strength 5.0-9.0 cN/dtex, breaking elongation 12-45%, entanglement degree 2.0-15. Polyester multifilament with 0/m and 3 to 15 filaments The polyester multifilament according to claim 1, wherein the high-viscosity polyester core component has an intrinsic viscosity of 0.70 to 1.50, and the low-viscosity polyester sheath component has an intrinsic viscosity of 0.40 to 0.70.