JP2010077563A - Polyester monofilament - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester monofilament having a small fineness capable of obtaining a high mesh screen gauze used for a highly minute screen printing, and satisfying both of a high strength and a high toughness. <P>SOLUTION: This polyester monofilament is a sheath core composite polyester filament consisting of a core component of a polyethylene terephthalate (PET) and sheath component of a polyethylene terephthalate having a lower intrinsic viscosity (IV) than that of the core component by ≥0.2, and having 3-8 dtex fineness, ≥7.5 cN/dtex strength and ≥29 toughness (strength × elongation<SP>0.5</SP>). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyester monofilament suitable for a high mesh screen wrinkle of # 400 (#: number of meshes, number of yarns per inch = 2.54 cm) or more.

  Conventionally, mesh fabrics made of natural fibers such as silk and inorganic fibers such as stainless steel have been widely used as screen printing fabrics, but recently synthetic fiber meshes with excellent flexibility, durability, and cost performance have been widely used. It has been. Among them, polyester monofilaments are highly suitable for screens because they have excellent dimensional stability and are widely used for high-precision printing of graphic designs such as label printing on compact discs and electronic circuit board printing.

  In recent years, as electronic devices have become more sophisticated and more compact, there have been fabric defects such as higher meshes and uneven diameters in order to meet the requirements for more compact electronic substrates and precision circuit boards. The demand for fewer screens is increasing. Therefore, it is essential that the polyester monofilament satisfying these screen wrinkling requirements has finer and higher strength, and at the same time, excellent in fine diameter uniformity and does not cause defects such as scum during weaving.

For example, a polyester monofilament in which both the core component and the sheath component are polyethylene terephthalate has high breaking strength and less scum generated by rubbing between the surface of the monofilament and the wings during weaving. However, the fineness described in the embodied example is as high as 10.0 dtex, which is not suitable for obtaining a high mesh screen wrinkle of # 400 or more (Patent Document 1). Further, there is a disclosure of an invention that has a fineness and high strength (Patent Document 2), but the toughness shown in the examples is brittle as about 27 at most because the elongation is greatly reduced by the fineness and strength. Since the yarn easily breaks due to slight tension fluctuations during warping and weaving, it is difficult to stably produce a high mesh screen wrinkle of # 400 or more with this polyester monofilament.
JP-A-2005-47020 (Claims, Examples) JP 2003-213520 A (Claims, Examples)

  An object of the present invention is to provide a polyester monofilament that has both fineness, high strength, and high toughness that can solve the above-mentioned problems and can provide a high mesh screen wrinkle used for high-precision screen printing.

In order to achieve the above object, the present invention adopts the following configuration. That is,
A core-sheath composite polyester monofilament composed of polyethylene terephthalate (PET) having a core component of polyethylene terephthalate having an intrinsic viscosity (IV) smaller than the core component by 0.2 or more, and having a fineness of 3 to 8 dtex and a strength of 7.5 cN / dtex or more Polyester monofilament having toughness (strength × elongation ^0.5 ) of 29 or more.

  Monofilaments suitable for high mesh screens for precision printing can be obtained.

  Hereinafter, the present invention will be described in detail.

  In the polyethylene terephthalate (hereinafter abbreviated as PET) in the present invention, 90 mol% or more of repeating units is ethylene terephthalate.

  The polyester monofilament of the present invention is a core-sheath type composite fiber in which both the core component and the sheath component are PET. The intrinsic viscosity (IV) of the sheath component is 0.2 or more smaller than IV of the core component, and preferably 0.3 or more. When the difference between the IV of the sheath component and the IV of the core component is less than 0.2 or when the IV of the sheath component is equal to or greater than the IV of the core component, the degree of molecular orientation of the resulting polyester monofilament surface layer is increased, so that weaving Sometimes fluffy or sticky scum tends to be generated by rubbing with the wings. Further, when the sheath component IV is 0.2 or more smaller than the core component IV, the sheath component bears the shear stress on the inner wall surface of the spinneret discharge hole of melt spinning, so that the shear force applied to the core component is reduced. Thereby, since the core component is spun in a uniform state with a low degree of molecular chain orientation, the strength of the finally obtained polyester monofilament is improved.

  The core component IV is preferably 0.7 or more, more preferably 0.8 or more, from the viewpoint of increasing the strength. On the other hand, from the viewpoint of the fluidity of the molten polymer in melt spinning, the core component IV is preferably 1.4 or less, and more preferably 1.3 or less.

  Since PET as the core component mainly bears the strength of the polyester monofilament, it is preferable that the additive of inorganic particles represented by titanium oxide usually added to the polyester fiber is less than 0.5 wt%.

  The sheath component IV is 0.2 or more smaller than the core component IV. From the viewpoint of stable meterability in a melt extruder or a spinneret, IV is preferably 0.4 or more.

  Since the sheath component PET mainly bears the abrasion resistance of the polyester monofilament, it is preferable to add about 0.1 to 0.5 wt% of inorganic particles typified by titanium oxide.

  Moreover, as long as the effect of this invention is not impaired, 10 mol% or less of copolymerization may be carried out to PET of a core component and a sheath component.

  Examples of copolymer components include acid components such as isophthalic acid, phthalic acid, dibromoterephthalic acid, naphthalene dicarboxylic acid, diphenylxyentanecarboxylic acid, bifunctional aromatic carboxylic acids such as oxyethoxybenzoic acid, sebacic acid, adipine Examples thereof include difunctional aliphatic carboxylic acids such as acid and oxalic acid, and cyclohexanedicarboxylic acid. Examples of the glycol component include propanediol, butanediol, neopentyl glycol, bisphenol A, and polyoxyalkylene glycols such as polyethylene glycol and polypropylene glycol.

  Furthermore, an antioxidant, an antistatic agent, a plasticizer, an ultraviolet absorber, a colorant, and the like may be appropriately added as additives to both the core component and the sheath component.

  The core / sheath area ratio of the polyester monofilament in the present invention is preferably 40/60 to 5/95. As described above, since the core component bears the strength and the sheath component bears the wear resistance, both effects can be achieved by setting the core component. More preferably, it is 30 / 70-10 / 90.

The fineness of the polyester monofilament of the present invention is 3 to 8 dtex. In order to obtain a high mesh screen wrinkle suitable for precision printing, preferably # 400 or more, more preferably # 450 or more, the fineness is 8 dtex or less. Conventional relatively high mesh screen wrinkles are approximately # 250 to 350, and monofilaments having a fineness of 10 to 20 dtex are used. However, in the case of a # 400 (400 per inch = 2.54 cm) high mesh screen ridge, the mesh lattice spacing per line is about 63 μm. When calculated based on the specific gravity of 1.38 g / cm ³ of a general polyester fiber, when a fineness of 10 dtex (diameter of about 30 μm) is used, the opening (aperture) per lattice is about 33 μm (52%), Since the clearance between the cocoon and the polyester monofilament is extremely small, scum is easily generated by rubbing between the cocoon wing and the polyester monofilament, and as a result, a # 400 or higher high mesh screen cocoon cannot be obtained. Therefore, the upper limit of the fineness of the polyester monofilament of the present invention is 8 dtex, and more preferably 6.5 dtex or less. The lower limit of the fineness is 3 dtex or more, more preferably 4 dtex or more in order to ensure the weaving property, particularly the weft flying property.

  The polyester monofilament of the present invention has a strength of 7.5 cN / dtex or more as a level that can sufficiently withstand the load in the weaving process to obtain a high mesh screen wrinkle from polyester monofilament with a fineness of 3-8 dtex and the load on screen printing. is there. Preferably it is 8.0 cN / dtex or more, More preferably, it is 8.5 cN / dtex or more.

  Yarn breakage is determined by the breaking strength and breaking elongation. Since the strength is related to the constant stress deformation and the elongation is related to the constant length deformation, even if the aforementioned strength of 7.5 cN / dtex is achieved, if the breaking elongation is small, the yarn is brittle and breaks. It can be said that it is easy.

Accordingly, the resistance to breakage should be expressed by parameters that take into account both the strength and the elongation, and not both. For example, in the stress-strain curve of the tensile test, the integrated value of the curve up to rupture corresponds to that, but if toughness (strength × elongation ^0.5 ) is used as a simple index, a good correlation is shown.

  In order to make a polyester monofilament with a fineness of 3 to 8 dtex into a high mesh screen wrinkle and further to be able to withstand printing as a screen wrinkle, the strength is set to 7.5 cN / dtex or more and the toughness is set to 29 or more as described above. To do. Preferably it is 31 or more, More preferably, it is 32 or more.

  The elongation of the polyester monofilament of the present invention is preferably 11% or more because the weaving property, particularly the tension at the time of weft insertion is stabilized, and yarn breakage is less likely to occur.

  From the viewpoint of equalizing the printing quality when precision printing is performed on a # 400 or higher high mesh screen and the strength and elongation characteristics of each of the individual meshes, the variation in yarn length of the polyester monofilament of the present invention is It is preferably 1.5% or less, more preferably 1.0% or less, and still more preferably 0.7% or less.

  In general, a Worcester measuring machine manufactured by Worcester is used for evaluation of the fineness unevenness in the yarn length direction of the fiber, but since the lower limit of detection of the measuring machine is 10 dtex, the fineness of 3 to 8 dtex like the polyester monofilament of the present invention is used. When the fine yarn is measured, the actual fineness unevenness is not sufficiently detected. Therefore, in order to evaluate the fineness unevenness of the polyester monofilament of 3 to 8 dtex, the fine diameter data obtained by the optical outer diameter measuring device is continuously collected in the yarn length direction, the data is calculated by the method described later, and the yarn length fineness variation ( %). It has been found that this method shows a value substantially equivalent to the Wooster value (normal) obtained by the Wooster measuring instrument.

In the spinning process for obtaining the polyester monofilament of the present invention, the PET of the core component and the sheath component are supplied to separate melt extruders, melted, weighed to a certain amount, discharged from the spinneret, and cooled and solidified. Take up with speed godet roller. In order to maximize the toughness of the obtained polyester monofilament, the following points should be mainly noted.
(1) The PET melting passage time and the heating temperature from melting to immediately before spinning are reduced as much as possible to suppress a decrease in the molecular weight of PET.
(2) The take-up speed by the godet roller is preferably a low speed of 800 m / min or less, more preferably 300 to 600 m / min, to suppress an increase in the degree of molecular orientation of the spun yarn.
(3) A heating element is provided directly below the spinneret, and preferably the atmospheric temperature is positively maintained at 260 ° C. or higher to suppress an increase in the degree of molecular orientation of the spun yarn due to stretching deformation.
(4) The spinning draft (= take-up speed / average linear velocity in the nozzle discharge port) is preferably 100 or less, more preferably 70 or less, and the deformation of the spun yarn on the spun line is moderated, and the molecular orientation of the spun yarn Suppress the degree.

  As a technique for improving toughness in the spinning process, (1) is to suppress the molecular weight decrease due to hydrolysis of PET as much as possible, and in addition, a spinning yarn having a small degree of molecular orientation in the spinning process can be obtained at a high draw ratio in the stretching process. From the viewpoint of orientation, (2) to (4) are effective to suppress the molecular orientation of the spun yarn as much as possible. In short, the degree of molecular orientation of the discharged yarn increases as the force of “stretching” by spinning increases. Examples of the force acting on the spinning line include a pulling force due to the take-up speed, a deformation resistance force due to stretching viscosity and an air resistance force, but in the case of a monofilament, the air resistance force is extremely small and may be almost ignored.

  When spinning by a conventional method to obtain a polyester monofilament having a fineness of 3 to 8 dtex, the spun yarn is thin and easily cooled, and the deformation resistance increases, so the molecular orientation of the spun yarn increases, resulting in toughness. Since it is difficult to obtain 29 or more, (2) to (4) are particularly important items.

  In order to reduce the tensile force due to the take-up speed, (2) the take-up speed by the godet roller is preferably 800 m / min or less, more preferably 300 to 600 m / min.

  In order to reduce the deformation resistance due to the extensional viscosity, from the viewpoint of increasing the yarn temperature during extensional deformation and lowering the extensional viscosity, (3) keeping the temperature just below the spinneret at 260 ° C. or higher, (4 ) If the spinning draft is small, specifically 100 or less, more preferably 70 or less, the toughness of the resulting polyester monofilament is improved.

  However, if the fine fiber of 3-8 dtex like the polyester monofilament of the present invention is too high in the atmosphere just below the base in order to obtain high toughness, or if the heating section until cooling is too long, the yarn length fineness will fluctuate. (%) Tends to be large, so care must be taken. These may be appropriately adjusted within a range in which the toughness can be maintained, but it is preferable that the atmosphere temperature below the die is the die surface temperature + 20 ° C. or less.

In the drawing / winding process for obtaining the polyester monofilament of the present invention, the spun yarn is drawn between a heated roller heated to a glass transition point or higher and a drawn roller heated to a crystallization temperature or higher. Wind up in a parn or cheese. In order to maximize the toughness of the obtained polyester monofilament, the following points should be mainly noted.
(5) From the viewpoint of reducing the fineness unevenness and physical property variation of the obtained monofilament, the undrawn yarn is not taken up once but directly drawn.
(6) Stretching is multistage stretching with three or more pairs of rollers, and the stretch ratio of the first stage is preferably 50 to 80%.
(7) The stretching roller temperature before the final stretching roller is preferably 130 ° C. or lower, more preferably 110 ° C. or lower to suppress crystallization during stretching.
(8) The temperature of the final drawing roller is preferably 180 ° C. or higher, more preferably 200 ° C. or higher to improve the crystallinity of the resulting polyester monofilament.

  Since the spun yarn obtained by the above spinning method has extremely low degree of orientation, once it is wound as an undrawn yarn, the molecular orientation and crystal state change over time until it is drawn, and the length tends to vary. . In particular, in order to obtain a fineness and high strength like the polyester monofilament of the present invention, a high-magnification drawing of 4.5 to 7.0 times is applied to an undrawn yarn of fineness, so that the molecular orientation / crystal of the undrawn yarn The difference in state is easily manifested as variation in yarn length fineness. If drawing is performed while the molecular orientation and crystal state of the undrawn yarn are uniform, fluctuations in yarn length fineness and variations in physical properties can be reduced. (5) Spin draw is preferred in which the yarn is drawn immediately without being wound once after spinning. .

  Further, in order to uniformly draw a monofilament undrawn yarn having a low degree of orientation and fineness, it is preferable to perform multi-stage drawing with a first-stage magnification ratio of 50 to 80% as in (6) and (7). The heating temperature of the previous stretching roller is preferably 130 ° C. or lower, more preferably 110 ° C. or lower. The upper limit of the number of rollers is not particularly limited, and if there are three or more pairs of hot rollers, the effect of multi-stage stretching can be obtained in the same way, but if the number is extremely increased, the apparatus becomes complicated, Usually about three or four pairs are sufficient. Regarding the hot roll, either a 1 hot roll-1 separate roll configuration or a 2 hot roll configuration (so-called duo type) may be used. In the duo type, one pair is counted by 2 hot rolls. is there.

  Furthermore, (8) The final stretching roller temperature for improving the crystallinity of the finally obtained polyester monofilament and obtaining high toughness is preferably 180 ° C. or higher, more preferably 200 ° C. or higher.

  Further, several godet rollers may be arranged between the final stretching roller and the winder. When a negative speed difference is imparted between the final stretching roller and the godet roller, the distortion of the molecular amorphous part caused by stretching can be alleviated, and the effect of increasing elongation and improving toughness, and scum The effect of improving wear resistance is obtained. On the other hand, when a positive speed difference is imparted between the final drawing roller and the godet roller, the initial elastic modulus of the resulting polyester monofilament is improved, so there is little misalignment when used as a high mesh screen wrinkle for printing. Accuracy is improved. These may be appropriately determined in consideration of the required characteristics for each printing application.

  In any part of the step of obtaining the polyester monofilament of the present invention, it is preferable to apply an oil agent for the purpose of improving the smoothness, abrasion resistance and antistatic property of the obtained polyester monofilament. Examples of the oiling method include an oiling guide method, an oiling roller method, and a spray method. The oiling method may be performed a plurality of times from spinning to winding.

  Hereinafter, the present invention will be described in detail with reference to examples. The evaluation in the examples followed the following method.

Intrinsic viscosity (IV)
0.8 g of sample was completely dissolved in 10 ml of orthochlorophenol and measured at 25 ° C.

(Fineness)
A value obtained by scraping 500 m of the yarn and multiplying the weight of the skein by 20 was defined as the fineness.

(Strength, elongation, toughness)
Using a Tensilon tensile tester manufactured by Orientex Co., Ltd., the strength and elongation at the time of breaking at an initial sample length of 20 cm and a tensile speed of 2 cm / min were measured, and the average value of the values measured 5 times each was determined as the strength (cN / dtex). ) And elongation (%). Further, toughness (strength × elongation ^0.5 ) was calculated from the strength and elongation.

(Yarn length fineness variation)
The obtained yarn is passed through a laser outer diameter measuring machine KL1002A / E detector manufactured by Anritsu Co., Ltd. at a speed of 500 m / min, and the yarn diameter of about 22000 points for 120 seconds under the output condition of 16 data averaged numbers. I got the data. The obtained yarn diameter data r (μm) was converted to yarn length fineness variation (%) by the following formula.

Here, n: number of data points, D _ave : average value of n D _i , D _i = 9.6 × (r _i ) ^0.5 ,
r _i : i-th data r
(Weaving evaluation)
A # 480 mesh woven fabric having a width of 2.2 m and a length of 300 m was woven with a loom loom at a rotation speed of 120 rpm. Attention was paid to the yarn breakage and wrinkle stain state at that time, and the determination was made according to the following index, and “◯” and “Δ” were regarded as acceptable.
○: Good (thread breakage 5 times or less and no wrinkle stain)
Δ: Good (both yarn breakage and wrinkle stains are in the range between ○ and ×)
×: Mass production is not possible (thread breakage is 15 times or more, or wrinkle stains continue and weaving is impossible)
(Print evaluation)
A 50 μm line pattern was formed at intervals of 50 μm with the photosensitive emulsion on the obtained mesh fabric, the state after printing was observed, and the determination was made according to the following indices.
○: Line reproduction is good, Δ: Concavities and convexities are seen at the boundary of the line, but there is no problem, ×: Defect (Example 1)
Melt with an individual extruder so that PET with an intrinsic viscosity of 1.15 polymerized and chipped by a conventional method becomes a core component and PET containing 0.3 wt% titanium oxide with an intrinsic viscosity of 0.63 becomes a sheath component. It was. The molten PET was passed through a pipe kept at 290 ° C., and then a core-sheath type composite yarn was spun from a known core-sheath type composite spinneret so that the core / sheath weight ratio was 8: 2. After the discharge yarn is positively kept warm by a heating body so that the ambient temperature is 290 ° C. ± 10 ° C. for 100 mm downward from the base surface, air at 25 ° C. is blown onto the yarn at a wind speed of 10 m / min, Cooled and solidified. The cooled and solidified yarn is supplied with a spinning oil by an oil supply roll, and then a godet roll 1 having a surface speed of 500 m / min, a surface speed of 505 m / min, a hot roll 2 having a surface temperature of 90 ° C., a surface speed of 1800 m / min, and a surface temperature of 100 A yarn whose speed is controlled so as to obtain a winding tension of 0.5 g after passing through a hot roll 3 having a surface temperature of 2930 m / min, a hot roll 4 having a surface temperature of 2930 m / min and a godet roll 5 having a surface speed of 2959 m / min. The polyester monofilament was wound up with a strip winder. At this time, the spinning draft was 64, the total draw ratio was 5.8 times, and the first-stage magnification ratio (first-stage draw ratio / total draw ratio × 100) was 62%. A schematic diagram of the yarn making process is shown in FIG. The fineness of the obtained monofilament was 4.5 dtex, the strength was 9.1 cN / dtex, the elongation was 13.1%, the toughness was 32.9, and the yarn length fineness variation was 0.49%. In the weaving evaluation using the obtained polyester monofilament, scum and yarn breakage were hardly generated, and the line reproducibility was good in printing evaluation.

(Examples 2 to 4, Comparative Example 1)
A polyester monofilament was obtained in the same manner as in Example 1 except that the fineness of the obtained polyester monofilament was changed as shown in Table 1. In Example 4, although there was some disturbance in line reproduction in printing evaluation, the printing performance was sufficient, but in Comparative Example 1, not only did scum-like defects occur in weaving, but line reproducibility in printing evaluation. Was insufficient.

(Examples 5-7, Comparative Example 2)
A polyester monofilament was obtained in the same manner as in Example 2, except that the raw material PET IV was changed as shown in Table 1. In Example 7, the strength and toughness were slightly reduced, so that yarn breakage occurred during weaving and printing resistance was reduced in printing evaluation, but sufficient performance was obtained. On the other hand, in Comparative Example 2, scum occurred frequently in weaving and could not be used.

  The results of Examples 1 to 7 and Comparative Examples 1 and 2 are shown in Table 1.

(Examples 8 and 9, Comparative Example 3)
A polyester monofilament was obtained in the same manner as in Example 1 except that the total draw ratio was changed to 5.3 times, 5.0 times, and 4.6 times, respectively. Since the strength decreased with a decrease in the draw ratio, in Example 8, yarn breakage during weaving increased, and in Example 9, an increase in yarn breakage during weaving and a decrease in printing resistance were observed. I had it. On the other hand, in Comparative Example 3, the strength was as low as 7.3 cN / dtex. Not only was the weaving property impossible to produce due to frequent yarn breakage during weaving, but also the printing accuracy and printing resistance were insufficient.

(Examples 10 to 12)
A polyester monofilament was obtained in the same manner as in Example 1 except that the amount of titanium oxide added to the raw material PET was changed as shown in Table 2. In Example 10, since the titanium oxide content of the core component was increased, a decrease in toughness was observed, and yarn breakage increased in weaving, but it was at a level that could be produced. In Example 12, since the titanium oxide content of the sheath component was reduced, the abrasion resistance of the polyester monofilament was reduced and scum was increased in weaving, but it was at a level that could be produced.

  The results of Examples 8 to 12 and Comparative Example 3 are shown in Table 2 above.

(Examples 13 to 15)
A polyester monofilament was obtained in the same manner as in Example 1 except that the heating temperature under the base was changed as shown in Table 3. In Example 13 in which the heating body temperature was raised, the yarn length variation of the polyester monofilament was increased, and the line reproducibility was lowered in the print evaluation, but it had sufficient performance. On the other hand, as the heating body temperature was lowered as in Examples 14 and 15, the toughness and elongation of the polyester monofilament were reduced, and in Example 15, yarn breakage in weaving and a decrease in printing resistance were observed. It had sufficient performance.

(Examples 16 and 17, Comparative Example 4)
A polyester monofilament was obtained in the same manner as in Example 1 except that the godet roll speed, the hot roll speed, and the heating body temperature were changed as shown in Table 3, and the fineness of the resulting polyester monofilament was made constant. In Example 17, although the toughness of the polyester monofilament was decreased, the yarn breakage during weaving was increased and the printing resistance was decreased, it had sufficient performance. On the other hand, in Comparative Example 4, toughness was remarkably reduced, yarn breakage during weaving occurred frequently, printing resistance was remarkably reduced, and it could not withstand substantial use.

(Examples 18 to 20)
In Examples 18 and 19, polyester monofilaments were obtained in the same manner as in Example 1 except that the speed of the hot roll 2 was changed as shown in Table 3 and that in Example 20 one-stage stretching was performed without using the hot roll 2. In both cases, sufficient performance was confirmed in weaving evaluation and printing evaluation, but in Example 19, thread breakage during weaving increased, and in Example 20, in addition to increased thread breakage during weaving, printing resistance decreased and printing increased. A decrease in line reproducibility was observed.

  The results of Examples 13 to 20 and Comparative Example 4 are shown in Table 3 above.

(Examples 21 to 24)
A polyester monofilament was obtained in the same manner as in Example 1 except that the temperatures of the hot rolls 3 and 4 were changed as shown in Table 4. In Examples 21 and 22, a decrease in toughness was observed as the temperature of the hot roll 3 increased, but a sufficient level was maintained. In Examples 23 and 24, a decrease in toughness was observed with a decrease in the temperature of the hot roll 4, but a sufficient level was maintained.

  The results of Examples 21 to 24 are shown in Table 4 above.

(Example 25, Comparative Example 5)
A polyester monofilament was obtained by a two-step method in which an undrawn yarn was spun by the same method as in Example 1, wound up after cooling and oiling, and then given drawing. The unstretched yarn obtained by changing the winding speed in spinning as shown in Table 5 was changed using a three-hot roll construction drawing machine, the draw ratio was changed as shown in Table 5, and the first stage draw ratio was 0.7. The roll temperatures were 90 ° C., 100 ° C., and 220 ° C. in order from the first roll, and the film was stretched at a final winding speed of 700 m / min. In Example 25, since the toughness compared to Example 1 was reduced, yarn breakage due to weaving, a decrease in printing resistance was observed, and a variation in yarn length fineness was increased, so a decrease in print line reproducibility was observed, but sufficient It had performance. On the other hand, in Comparative Example 5, the toughness was further lowered compared to Example 25, yarn breakage occurred frequently in weaving, print resistance was remarkably lowered, and the material was not practically usable.

  The results of Example 25 and Comparative Example 5 are shown in Table 5 above.

It is a spinning equipment schematic diagram showing one embodiment of the present invention.

Explanation of symbols

1: Base 2: Heating body 3: Cooling air blowing surface 4: Oil supply roll 5: Godet roll 1
6: Hot roll 2
7: Hot roll 3
8: Hot roll 4
9: Godet Roll 5
10: Yarn winding device

Claims (2)

A core-sheath composite polyester monofilament composed of polyethylene terephthalate (PET) having a core component of polyethylene terephthalate having an intrinsic viscosity (IV) smaller than the core component by 0.2 or more, and having a fineness of 3 to 8 dtex and a strength of 7.5 cN / dtex or more Polyester monofilament having toughness (strength × elongation ^0.5 ) of 29 or more.   The polyester monofilament according to claim 1, wherein the yarn length fineness variation is 1.5% or less.

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