JP2011021296A - Monofilament for screen gauze, excellent in dimensional stability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monofilament which is excellent in weaving stability on processing and in dimensional stability required for continuous printing performance, and is suitable for obtaining high mesh high modulus screen gauze. <P>SOLUTION: The polyester monofilament for the screen gauze is characterized in that the polyester is polyethylene terephthalate containing a phosphorus compound comprising phenyl phosphonic acid or a derivative thereof, and/or phenyl phosphinic acid or a derivative thereof in an amount of 0.1 to 300 mmole% based on the mole number of a dicarboxylic acid constituting the polyester. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyester monofilament suitable for obtaining a high-mesh, high-modulus screen wrinkle that requires high precision, such as mesh fabric for screen printing, particularly for the production of printed wiring boards.

  Monofilaments have been widely used not only in the clothing field but also in the industrial material field. Examples of applications in the latter field of industrial materials in particular include monofilaments as raw yarns for tire cords, ropes, nets, tegus, tarpaulins, tents, screens, paragliders and sailcloths. The physical properties required for this monofilament are becoming strict, and improvements such as adhesion to rubber, fatigue resistance, dyeability, abrasion resistance, and knot strength are being urged. Especially in the recent printing in the electronic circuit field, the degree of integration is increasing, and there is a demand for higher printing density and improved printing as screen screens, that is, high strength, high modulus and high mesh. It is getting stronger. Therefore, the raw yarn is required to have high strength, high modulus, and fineness.

  JP-A-2-289120 proposes a specific value for the rupture strength and elongation of a raw yarn before weaving when the screen yarn is designed. However, in the production of screen wrinkles, since the texture adjustment, heat setting, and tensioning processes are performed, the strength and elongation of the yarn changes due to wet heat treatment after weaving. However, there was a problem that the dimensional stability at the time of precision printing of the screen 欠 け was lacking.

  Japanese Patent Laid-Open No. 2-277818 discloses that a monofilament for a screen with good dimensional stability can be obtained by setting the strength, the strength at 12.5% elongation, and the dry heat shrinkage within a specific range. Yes. However, there are wet heat processes such as refining and dyeing processes in the screen wrinkle manufacturing process, which does not take into account changes in the physical properties of the yarn due to wet heat shrinkage, etc. and is not satisfactory in fields that require high dimensional stability. It was.

  Japanese Patent Application Laid-Open No. 2005-47020 proposes to set specific values for breaking strength, elongation, and boiling water shrinkage as raw yarn physical properties. This method takes into account the shrinkage in the wet heat process, and although the dimensional stability is improved to some extent, it does not prescribe the physical properties of the yarn before and after shrinkage, so the dimensional stability varies between lots of screen wrinkles. It was subject to equal stability.

  Furthermore, in order to demonstrate sufficient performance for screen wrinkles, the raw yarn physical properties before weaving are adjusted as described above, and then subjected to a weaving process, followed by wet heat treatment such as refining, dyeing, etc. Although it shrinks by passing, it has to have a predetermined strength and elongation characteristic after the wet heat shrinkage, and it is further necessary that the fiber diameter is stable along the yarn length direction. In particular, the knots on the surface of the monofilament are undesirable because they cause yarn breakage and scum at the time of weaving, and it is necessary to prevent them from occurring as much as possible. The present situation is that the characteristics are not fully satisfied.

JP-A-2-289120 JP-A-2-277818 JP-A-2005-47020

  An object of the present invention is to provide a high-mesh, high-modulus polyester monofilament for screen wrinkles having a uniform fiber diameter and excellent continuous printing performance, particularly dimensional stability.

  The present invention was obtained as a result of diligent studies to solve the above-mentioned problems, and by controlling the crystal growth of the polyester produced in the spinning and drawing processes by making the polyester contain a specific phosphorus compound (uniformization). This makes it possible to obtain a yarn having a uniform fiber diameter, few nodes, and good dimensional stability.

［上の式中、Ｒ^１は炭素数１〜１２個の炭化水素基であるアルキル基、アリール基又はベンジル基であり、Ｒ^２は水素原子又は炭素数の１〜１２個の炭化水素基であるアルキル基、アリール基又はベンジル基、Ｘは、水素原子または−ＯＲ^３基であり、Ｘが−ＯＲ^３基である場合、Ｒ^３は水素原子又は炭素数の１〜１２個の炭化水素基であるアルキル基、アリール基又はベンジル基、であり、Ｒ^２とＲ^３は同一であっても異なっていても良い。］
好ましくは該ポリエステル繊維が１〜１００ｎｍの層状構造を有する粒子を含有し、赤道方向の広角Ｘ線回折において２θ=５〜６°に回折ピークを有するスクリーン紗用ポリエステルモノフィラメント。
が提供される。 That is, according to the present invention,
In a polyester monofilament for screen wrinkles, a polyester is a main repeating unit of ethylene terephthalate, a phenylphosphonic acid represented by the following formula (1) or a derivative thereof, and / or a phosphorus compound that is a phenylphosphinic acid or a derivative thereof, A polyester monofilament for screen wrinkles, which is a polyethylene terephthalate composition containing 0.1 to 300 mmol% with respect to the total number of moles of dicarboxylic acid constituting the polyester, and satisfies the following requirements A to D.
A. Monofilament yarn strength before wet heat treatment is 5.0 to 7.0 cN / dtex, strength at 5% elongation is 2.5 to 3.7 cN / dtex, elongation is 20 to 45%, wet heat shrinkage is 2 .5 to 9.0%.
B. The intrinsic viscosity of the polyester is 0.70 to 1.00 dL / g.
C. The single yarn fineness is 1 to 24 dtex.
D. The number of knots is 1.1 or more times the fiber diameter in the monofilament longitudinal direction of 500,000 meters.

[In the above formula, R ¹ is an alkyl group, aryl group or benzyl group which is a hydrocarbon group having 1 to 12 carbon atoms, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. A certain alkyl group, aryl group or benzyl group, X is a hydrogen atom or —OR ³ group, and when X is a —OR ³ group, R ³ is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. An alkyl group, an aryl group or a benzyl group, and R ² and R ³ may be the same or different. ]
A polyester monofilament for screen wrinkles, wherein the polyester fiber preferably contains particles having a layered structure of 1 to 100 nm and has a diffraction peak at 2θ = 5 to 6 ° in wide-angle X-ray diffraction in the equator direction.
Is provided.

  In the polyester monofilament for screen wrinkles, by containing a specific phosphorus compound in the polyester, the crystal growth of the polymer can be suppressed and a fiber having a uniform fiber diameter can be obtained, and yarn scraping in the weaving process can be prevented. Further, by setting the properties of the yarn before weaving, the shrinkage rate, and the properties of the yarn after the wet heat treatment after weaving to specific values, a screen wrinkle with good dimensional stability in precision printing can be obtained stably.

  A fine filament monofilament of 1 to 24 dtex is used for a high mesh screen (200 to 500 mesh) suitable for precision printing. The polyester polymer constituting the monofilament for screen wrinkles of the present invention comprises a phosphorus compound in which the polymer is phenylphosphonic acid or a derivative thereof, and / or phenylphosphinic acid or a derivative thereof, relative to the number of moles of dicarboxylic acid constituting the polyester. 0.1 to 300 mmol% of the polymer composition.

The polyester polymer of the present invention contains phenylphosphonic acid or a derivative thereof and / or a phosphorus compound that is phenylphosphinic acid or a derivative thereof, thereby improving the crystallinity of the polymer, melting, and discharging from a spinneret. In the stage, a large number of microcrystals are formed. These microcrystals finely disperse and homogenize the crystal growth that occurs in the spinning and drawing processes, thereby making the fiber diameter uniform, and the yarn scraping and scum generated by the plastic deformation of the fiber during high mesh knit weaving. Occurrence can be reduced. The polyester polymer used in the present invention preferably has a limiting viscosity of the resin chip in the range of 0.60 to 1.20 by performing known melt polymerization or solid phase polymerization. If the intrinsic viscosity of the resin chip is too low, it is difficult to increase the strength of the fiber after melt spinning. On the other hand, if the intrinsic viscosity is too high, the solid-state polymerization time is greatly increased and the production efficiency is lowered, which is not preferable from an industrial viewpoint. The intrinsic viscosity is preferably in the range of 0.65 to 1.0. In order to form a large number of microcrystals, R ^{1 of the} phosphorus compound represented by the following general formula (1) is preferably a benzyl group, more preferably a phenyl group, and the phosphorus compound of the present invention. Is preferably phenylphosphinic acid or phenylphosphonic acid. In particular, phenylphosphonic acid and its derivatives are optimal.

［上の式中、Ｒ^１は炭素数１〜１２個の炭化水素基であるアルキル基、アリール基又はベンジル基であり、Ｒ^２は水素原子又は炭素数の１〜１２個の炭化水素基であるアルキル基、アリール基又はベンジル基、Ｘは、水素原子または−ＯＲ^３基であり、Ｘが−ＯＲ^３基である場合、Ｒ^３は水素原子又は炭素数の１〜１２個の炭化水素基であるアルキル基、アリール基又はベンジル基、であり、Ｒ^２とＲ^３は同一であっても異なっていても良い。］

[In the above formula, R ¹ is an alkyl group, aryl group or benzyl group which is a hydrocarbon group having 1 to 12 carbon atoms, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. A certain alkyl group, aryl group or benzyl group, X is a hydrogen atom or —OR ³ group, and when X is a —OR ³ group, R ³ is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. An alkyl group, an aryl group or a benzyl group, and R ² and R ³ may be the same or different. ]

  The phosphorus compound content in the polyester polymer is preferably 0.1 to 300 mmol% based on the number of moles of the dicarboxylic acid component constituting the polyester. If the amount of the phosphorus compound is less than 0.1 mmol%, the crystallinity improving effect of the microcrystals tends to be insufficient, and if it exceeds 300 mmol%, foreign matter defects are generated during spinning, so that the spinning property is improved. Tend to decrease. The content of the phosphorus compound is more preferably in the range of 1 to 100 mmol%, more preferably in the range of 10 to 80 mmol%, based on the number of moles of the dicarboxylic acid component constituting the polyester.

  Also included in the polymer are various additives such as matting agents such as titanium dioxide, heat stabilizers, antifoaming agents, color adjusters, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, fluorescent enhancers. Contains additives such as montmorillonite, bentonite, hectorite, plate-like iron oxide, plate-like calcium carbonate, plate-like boehmite, or carbon nanotubes as whitening agents, plasticizers, impact-resistant additives, or reinforcing agents It goes without saying.

  The polyester monofilament for screen wrinkles of the present invention is characterized in that layered nanoparticles of a phosphorus compound having a size of 1 to 100 nm are formed and contained in the polyester by containing these phosphorus compounds. Such layered nanoparticles in the fiber can be confirmed by a transmission electron microscope. When the size of the layered nanoparticles exceeds 100 nm, it acts as a foreign substance in the fiber, and breakage or single yarn breakage is likely to occur, resulting in a decrease in mechanical properties such as strength and modulus. On the other hand, when the thickness is less than 1 nm, it is difficult to obtain effects such as improvement of crystallinity of the polyester polymer, which is important in the present invention, improvement of yarn production, and uniform fiber diameter. The size of such layered nanoparticles is preferably 5 to 80 nm, and more preferably 10 to 60 nm. Furthermore, the polyester fiber of the monofilament for industrial material screens of the present invention contains particles having a layered structure of 1 to 100 nm and has a diffraction peak at 2θ = 5 to 6 ° in wide-angle X-ray diffraction in the equator direction. It is essential. This indicates that the layered nanoparticles having an interlayer spacing of several nanometers are specifically oriented in the fiber axis direction. It was found that the yarn was suppressed and the productivity was dramatically improved.

  The monofilament for a screen wrinkle of the present invention needs to have specific properties such as specific strength and elongation enough to suppress the occurrence of deterioration in weaving property and screen wrinkle. Generally, the performance is evaluated by a stress at 5% elongation (modulus, hereinafter referred to as 5% ASE). In order to obtain a higher degree of dimensional stability, the present inventor It has been found that it is important to consider the influence of the yarn on the wet heat treatment in the manufacturing process. Based on these findings, according to the present invention, the screen filament monofilament uses a high IV polyester polymer of 0.7 to 1.0 dL / g, and the fineness of the single yarn is 1 to 24 dtex. Monofilament, the strength before wet heat treatment of the monofilament is 5.0 to 7.0 cN / dtex, the strength at 5% elongation is 2.5 to 3.7 cN / dtex, the elongation is 20 to 45%, the wet heat shrinkage rate 2.5-9.0%, strength after wet heat treatment is 5.0-6.5 cN / dtex, strength at 15% elongation is 3.0-5.0 cN / dtex, and elongation is 20-40 By setting the ratio to%, a screen wrinkle that is highly excellent in dimensional stability can be obtained as a screen wrinkle after the process of texture adjustment, wet heat setting and tensioning.

Examples of the polyester used include aromatic polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), and any of them may be used. Among these, PET is most preferable in terms of operability and cost when performing melt spinning.
In order to obtain a high mesh screen wrinkle, the fineness of the monofilament is 1 to 24 dtex, preferably 4 to 20 dtex, more preferably 5 to 15 dtex.

The monofilament of the present invention has a strength before wet heat treatment of 5.0 to 7.0 cN / dtex, a strength at 5% elongation (abbreviated as 5% LASE) of 2.5 to 3.7 cN / dtex, and an elongation of 20 to Design to 45% and wet heat shrinkage of 2.5-9.0%.
A higher 5% LASE is preferable, but if it exceeds 3.7 cN / dtex, it is not preferable because scraping due to wrinkles occurs during weaving and is woven into the woven fabric, resulting in defects. Conversely, if it is less than 2.5 cN / dtex, it is not preferable because sufficient fabric strength cannot be obtained.
The wet heat shrinkage rate is preferably in the range of 2.5 to 9.0%, and outside this range, the 15% elongation stress after the wet heat treatment cannot be within a specific range, which is not preferable.

In the present invention, it is important to improve the dimensional stability of the screen wrinkles after the wet heat treatment by using the strength of the raw yarn after the wet heat treatment and the strength at 15% elongation as an index. It is necessary that the later strength is 5.0 to 6.5 cN / dtex, the strength at 15% elongation is 3.0 to 5.0 cN / dtex, and the elongation is 20 to 40%.
If the strength after wet heat treatment is less than 5.0 cN / dtex, the screen wrinkle strength is insufficient and tearing is likely to occur during tensioning. Is likely to occur.

On the other hand, if the elongation is less than 20%, the yarn handling property is deteriorated, for example, the weaving yarn breakage frequently occurs. If the elongation is 45% or more, wrinkle elongation is likely to occur.
Although the specific manufacturing method for obtaining the monofilament of this characteristic is demonstrated, it is not necessarily limited to this.

  By using a spinneret, melt spinning is performed to obtain a monofilament, followed by drawing to obtain a raw yarn having the above physical properties. In the spinning step, as a step of winding and redrawing as an undrawn yarn, the spinning speed is 400 to 1000 m / min, and it is preferable to draw 3.0 to 10 times after spinning. Further, the spinning speed is preferably 400 to 600 m / min. Moreover, it is preferable that it is 3-7 times as a draw ratio. Thus, it is possible to obtain a drawn fiber with higher strength by spinning at a low speed and drawing at a high magnification. Conventionally, even when spinning at a low speed, there is a portion having a weak strength due to a crystal defect at the time of high-strength drawing, and therefore, yarn breakage often occurs at the time of high-strength drawing. However, in the present invention, fine crystals are uniformly formed in the crystallization by stretching by blending the phosphorus compound, so that stretching defects are hardly generated, the fibers can be stretched at a high magnification, and the fibers can be strengthened. It is.

  As a stretching method in the method for producing a polyester monofilament according to the present invention, the polyester monofilament may be temporarily wound from a take-up roller and may be stretched by another so-called stretching method, or undrawn yarn is continuously supplied from the take-up roller to the stretching process. The so-called direct stretching method may be used for stretching. Further, the stretching conditions are one-stage or multi-stage stretching, and it is preferable to use several pairs of heating rolls, and it is preferable to stretch in one or more stages, and finally the stretching is performed so that the strength, elongation, and shrinkage rate are within a predetermined range. Determine the magnification. This stretching includes relaxation treatment such as relaxation stretching. The stretching load factor is preferably 60 to 95%. The drawing load factor is the ratio of the tension at the time of drawing to the tension at which the fiber actually breaks.

  In this way, the properties of the raw yarn before weaving are adjusted, and then subjected to the weaving process, and if necessary, shrinkage is performed by wet heat treatment such as refining, dyeing, etc. The resulting screen has a high degree of dimensional stability.

  Nodes generated on the surface of the monofilament are undesirable because they cause yarn breakage and scum during weaving, and it is necessary to prevent them from occurring as much as possible. As the cause of the knot, there are unmelted foreign matters contained in the polymer and deterioration of the polymer itself. About the unmelted foreign material in a polymer, the discharge | emission can be suppressed or disperse | distributed by forming a filtration layer from a pack entrance to a nozzle | cap | die discharge port. The filtration layer preferably has an opening of about 10 to 15% of the monofilament diameter, and if it is less than 10%, abnormal pressure is applied in the pack, leading to damage to the pack internal parts and the pack body. If it exceeds 15%, unmelted foreign matter that is the main cause of knotting is contained in the yarn as coarse particles, and the risk of knotting increases. In addition, with regard to the deterioration of the polymer itself, with regard to polymer feeding, the bending of the pipe is reduced, the time from introduction of the pack to discharge is within 1 minute, and the amount of heat received by the polymer is reduced as much as possible to reduce the risk of occurrence of nodes. be able to.

The present invention will be described more specifically with reference to the following examples.
In Examples, intrinsic viscosity, strength, elongation, shrinkage ratio during wet heat treatment, strength after wet heat treatment, elongation after wet heat treatment, strength at 15% elongation, evaluation of number of nodes, evaluation of thread scraping, hysteresis Evaluation was performed according to the following definitions.

Intrinsic viscosity:
Dilution solutions of each concentration (C) in which the sample was dissolved in orthochlorophenol at 35 ° C. were prepared, and C was brought close to 0 from the viscosity (ηr) of these solutions by the following formula.
η = limit (ln (ηr / C))

Wide-angle X-ray diffraction of fibers:
Using a D8 DISCOVER with GADDS Super Speed manufactured by Bruker, wide-angle X-ray diffraction in the equator direction of the fiber at a diffraction angle of 2θ = 0 ° to 50 ° was measured to determine the presence or absence of a diffraction peak at 2θ = 5 to 6 °. Moreover, the particle | grain form and particle | grain size which exist in a fiber were calculated | required from the transmission electron microscope observation.

Fineness, strength, elongation:
The fineness, strength, and elongation of the fiber are the strength and elongation when the sample is broken, measured according to JIS-L1017, using a Tensilon manufactured by Orientec Co., Ltd., with a sample length of 25 cm and an elongation rate of 30 cm / min. 5% LASE measured the stress when the sample at the time of the above measurement was extended by 5%.

Moist heat shrinkage:
5000 m was sampled and placed in a skein state, and the wet heat treatment was performed for 10 minutes while applying a fineness of 0.1 times (g) in a humid heat atmosphere at 130 ° C. in high pressure. The yarn after the treatment was naturally dried and the yarn length was measured again. The yarn length after the treatment was divided by the yarn length of 5000 m before the treatment, and the percentage of shrinkage after the wet heat treatment was expressed as a percentage.

Strength after wet heat treatment, elongation, 15% ASE:
The strength and elongation of the fiber after wet heat treatment are the strength and elongation when the yarn after wet heat treatment is measured at a sample length of 25 cm and an elongation rate of 30 cm / min using Tensilon manufactured by Orientec Co., Ltd. . For 15% ASE, the stress was measured when the sample at the time of the above measurement was extended by 15%.

Evaluation of number of nodes:
In front of the dropper installed at the creel outlet of the warping machine, 12 slit guides having a clearance of thread diameter × 1.1 times and a tolerance of ± 2 μm were installed. Threads were passed through the slit guide, and 12 yarns × 8 stages = 96 yarns were warped at a yarn speed of 500 m / min, and each yarn length was 200,000 m. At that time, the number of yarn breaks with the slit guide was regarded as the number of knots, and the number of yarn breaks during warping was measured. Evaluation was performed by converting the detected number of times of yarn breakage into a yarn length of 100,000 m.

Evaluation of thread cutting:
A mesh fabric was woven using 300 warps per inch of weaving width with a slewer type loom at a rotation speed of 250 rpm, and the woven fabric was visually inspected with the inspection machine. At this time, the number of fabric defects in which the mesh pattern that normally appears black was whitened was counted and evaluated.
Less than 5 defects due to thread scraping per woven width 1.5 m × fabric length 30 m were evaluated as ◯, 5 or more and less than 10 as Δ, and 10 or more as X.

[Example 1]
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, 0.06 part of calcium acetate monohydrate (0.066 mol% with respect to dimethyl terephthalate) and 0.013 part of cobalt acetate tetrahydrate as a color adjuster (terephthalic acid) 0.01 mol% with respect to dimethyl) was charged into a transesterification reactor, and the reaction product was heated from 140 ° C. to 220 ° C. over 4 hours under a nitrogen gas atmosphere. The ester exchange reaction was carried out while distilling out. Subsequently, 0.03 part by weight (50 mmol%) of phenylphosphonic acid (PPA) was added before the end of the transesterification reaction. Thereafter, 0.058 part of trimethyl phosphate (0.080 mol% based on dimethyl terephthalate) as a stabilizer and 0.024 part of dimethylpolysiloxane as an antifoaming agent were added to the reaction mixture. Next, after 10 minutes, 0.041 part of antimony trioxide (0.027 mol% with respect to dimethyl terephthalate) was added to the reaction mixture, and the temperature was raised to 240 ° C. while distilling off excess ethylene glycol. Thereafter, the reaction mixture was transferred to a polymerization reactor. Subsequently, the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour and 40 minutes and the temperature was raised from 240 ° C. to 280 ° C. to cause a polycondensation reaction, and then converted into chips according to a conventional method to obtain a polyester resin chip having an intrinsic viscosity of 0.65. This chip was preliminarily dried at 120 ° C. for 2 hours under a vacuum of 65 Pa, and then subjected to solid state polymerization at 240 ° C. for 10 to 13 hours under the same vacuum to obtain a polyester resin chip having the intrinsic viscosity shown in Table 1.

Production of monofilament:
The yarn production was performed as follows. The above-mentioned dry resin chip was melted by a conventional method in a spinning facility and supplied to a spinning head heated to 290 ° C. through a gear pump. The molten polymer is cooled and solidified from a spinneret having one circular spinning hole having a nozzle hole diameter of 0.25 mm with cooling air from a normal cross-flow type spinning cylinder, and a spinning oil is applied while spinning at 1200 m / min. While being wound at a high speed, an undrawn yarn was obtained while attaching an oil agent with an oiling roller. Then, after preheating with a heated hot roller, it was stretched at 3.8 times while being heated at 200 ° C., subjected to a relaxation treatment of 0.03 times, wound up, and a 13 dtex-1fil stretched yarn was drawn. Obtained. The obtained drawn yarn had a strength of 5.2 cN / dtex, an elongation of 32%, a 5% ASE of 4.0 cN / dtex, and a wet heat shrinkage of 2.8%. Table 1 shows the properties of polyester and raw yarn. The number of node yarn generation of the raw yarn was zero. When this raw yarn was woven with a slewer type loom, the number of fabric defects due to the occurrence of yarn shaving was 0 per 30 m. When the finished screen koji was continuously printed, it had little elongation and excellent dimensional stability.

[Example 2]
In Example 1, a monofilament was obtained in the same manner as in Example 1 except that solid phase polymerization was not performed during polyester production. Table 1 shows the properties of polyester and raw yarn.

[Example 3]
In Example 1, when producing polyester, it carried out like Example 1 except having used 100 mmol% of phenylphosphinic acid (PPI) instead of phenylphosphonic acid (PPA), and obtained the monofilament. Table 1 shows the properties of polyester and raw yarn.

[Example 4]
In Example 1, a monofilament was obtained in the same manner as in Example 1 except that 80 mmol% of phenylphosphinic acid (PPI) was used instead of phenylphosphonic acid (PPA) during polyester production. Table 1 shows the properties of polyester and raw yarn.

[Comparative Example 1]
In Example 1, when manufacturing polyester, it implemented similarly to Example 1 except not containing a phosphorus compound, and obtained the chip | tip which consists of a polyester composition. Using this tip, melt spinning was carried out in the same manner as in Example 1 to obtain an undrawn yarn to obtain a monofilament. Table 1 shows the properties of polyester and raw yarn.

[Comparative Example 2]
In Example 1, a chip made of a polyester composition was obtained in the same manner as in Example 1 except that 40 mmol% of normal phosphoric acid was added as a phosphorus compound in place of phenylphosphinic acid. Using this tip, melt spinning was carried out in the same manner as in Example 1 to obtain an undrawn yarn to obtain a monofilament. Table 1 shows the properties of polyester and raw yarn.
The results of Examples 1-4 and Comparative Examples 1-2 are summarized in Table 1.

  The polyester monofilament of the present invention is suitable for obtaining a high mesh and high modulus screen wrinkles required for high precision such as mesh fabric for screen printing, production of printed wiring board and the like.

Claims (2)

In a polyester monofilament for screen wrinkles, a polyester is a main repeating unit of ethylene terephthalate, a phenylphosphonic acid represented by the following formula (1) or a derivative thereof, and / or a phosphorus compound that is a phenylphosphinic acid or a derivative thereof, A polyester monofilament for screen wrinkles, which is a polyethylene terephthalate composition containing 0.1 to 300 mmol% with respect to the total number of moles of dicarboxylic acid constituting the polyester, and satisfies the following requirements A to D.
A. Monofilament yarn strength before wet heat treatment is 5.0 to 7.0 cN / dtex, strength at 5% elongation is 2.5 to 3.7 cN / dtex, elongation is 20 to 45%, wet heat shrinkage is 2 .5 to 9.0%.
B. The intrinsic viscosity of the polyester is 0.70 to 1.00 dL / g.
C. The single yarn fineness is 1 to 24 dtex.
D. The number of knots is 1.1 or more times the fiber diameter in the monofilament longitudinal direction of 500,000 meters.

[In the above formula, R ¹ is an alkyl group, aryl group or benzyl group which is a hydrocarbon group having 1 to 12 carbon atoms, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. A certain alkyl group, aryl group or benzyl group, X is a hydrogen atom or —OR ³ group, and when X is a —OR ³ group, R ³ is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. An alkyl group, an aryl group or a benzyl group, and R ² and R ³ may be the same or different. ]   The polyester monofilament for a screen wrinkle according to claim 1, wherein the polyester fiber contains particles having a layered structure of 1 to 100 nm and has a diffraction peak at 2θ = 5 to 6 ° in wide-angle X-ray diffraction in the equator direction.