JP2005240266A - Polyester monofilament for screen mesh - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester monofilament for screen mesh having excellent homogeneity of filament diameter and scum suppressing effect together with dimensional stability. <P>SOLUTION: The polyester monofilament for precise mesh screen comprises a sheath-core polyester conjugate monofilament for screen mesh wherein the core polymer has 0.71-1.30 of IV, ≥6.0 cN/dtex of breaking tenacity, less than one predetermined knotted portion per 1,000,000 meter. And the sheath polymer contains 0.35-0.60 wt.%. of inorganic particles containing ≥60% of particles having ≤0.50 μm of particle diameter and the polymer has ≥6.0 cN/dtex of breaking tenacity and the polyester monofilament is used for high mesh screen. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polyester monofilament for precision screens and a polyester monofilament for high mesh screens, and more specifically, screens used for application of electrode paste to a front electrode substrate and a back electrode substrate constituting a plasma display, and The present invention relates to a polyester monofilament used for a screen wrinkle having a weaving density of 355 mesh or more used for CD printing or graphic printing, that is, the number of warp and weft yarns is 355 or more per inch.

  Conventionally, mesh fabrics made of natural fibers such as silk and inorganic fibers such as stainless steel have been widely used as printing screen fabrics. However, in recent years, synthetic fabric meshes that excel in flexibility, durability, and cost performance have been favored. Among them, polyester monofilaments are widely used because they are highly suitable for screens such as excellent dimensional stability.

  In recent years, with the spread of home-use plasma display televisions in the home appliance industry, compact discs such as application of electrode paste to the front electrode substrate and back electrode substrate constituting the plasma display (hereinafter referred to as PDP) and electronic circuit printing With the popularization of CD (hereinafter abbreviated as “CD”) and the printing and publication of computer-designed designs becoming mainstream, attempts to use synthetic fiber meshes for thermal stencil printing, etc. have been made, the mesh is finer, the wire diameter Is required, and a screen wrinkle having little dimensional elongation and excellent dimensional stability is required. In particular, in the electrode paste application in the PDP, the defect of the mesh fabric immediately becomes the uneven thickness of the electrode paste, resulting in the image defect in the PDP television and the like. It is known that monofilaments containing knots exceeding twice cannot be used at all, and in CD printing and graphic printing, the defects of mesh fabrics immediately become printing defects and the commercial value is lost.

  Also, in general, the screen wrinkling process involves weaving a high-density fabric at a high speed. Therefore, in high-density weaving, the contact frequency and frictional force between the running filament and the small-pitch blades increase, and the filament surface is scraped off. As a result, beard-like or powder-like scum is likely to occur. Not only does this scum become soiling on the loom, but if it is woven into the screen wrinkles, it becomes a serious drawback in precision printing.

  In other words, in order to satisfy the required quality in the above-mentioned applications, a fine yarn, high strength, high modulus, no irregularity in the longitudinal direction of the fiber, high wire diameter uniformity, no scum generation, etc. Providing is an important issue.

  Conventionally, many proposals have been made on improvement techniques for reducing the occurrence of scum and increasing the strength of screen filament monofilaments.

  For example, the core part is polyethylene terephthalate with IV = 0.60-0.90, the sheath part is IV = 0.60-0.80, and isophthalic acid 8-20 mol%, neopentyl glycol 5-14 mol% copolymerization It is the composite monofilament made into the polyethylene terephthalate of the Vicat softening temperature 67-78 degreeC (refer patent document 1). As another proposal, the core-sheath type composite monofilament has a breaking strength of 6 g / d (5.29 cN / dtex) or more and a modulus at an elongation of 10% of 3.5 g / d (3.08 cN / dtex) or more. The elongation at break is less than 33%, the glass transition temperature (Tg) of the polyester forming the sheath is lower than that of the core and is 35 to 73 ° C., and the core: sheath area ratio is 70: 30-95. : 5 is a polyester monofilament for screen wrinkles (see Patent Document 2). In these monofilaments, when the softness of the polymer is improved by reducing the glass transition temperature and softening temperature by using a copolyester as the sheath part, it has the effect of reducing the occurrence of scum, but for complete prevention In addition, the strength required for screen yarns and the stress at 10% elongation to achieve higher density and improved dimensional stability required for high-precision printing screens such as electronic circuit printing It is very difficult to realize important raw material properties such as. In these proposals, for the purpose of obtaining strength, polyester in the range of IV = 0.60-0.90 is simply melt-spun using a core part, but polyester is melted in these monofilaments. The gelled product generated by heat deterioration during spinning is mixed in the discharged yarn, and a significantly thick knot is generated locally with respect to the normal part fineness, and a monofilament with high uniformity of the wire diameter cannot be obtained. A screen flaw suitable for high-precision printing of PDP cannot be obtained.

Further, as another proposal, in the core-sheath type composite monofilament, the core polymer has an intrinsic viscosity of 0.70 or more, the sheath polymer has an intrinsic viscosity of 0.40 or more, and a breaking strength of 5.5 cN / dtex or more. Polyester monofilament for use (see Patent Document 3). In these monofilaments, the sheath part is a copolyester to lower the glass transition temperature and softening temperature, or simply to make the polyester extremely low in intrinsic viscosity, thereby improving the softness of the polymer and reducing the occurrence of scum. As shown in the figure, the scum generation at the blades in the high mesh screen woven weaving 355 mesh or more by the slewer weaving machine is not completely prevented, and not only the screen cocoon productivity is inferior, but also the scum is generated in a fibrous form. Since it is easy, fibrous scum is woven into the screen so as to induce a printing defect when used for high-precision printing such as CD printing or graphic printing.
JP-A-11-241227 (Claims) JP-A-2-289120 (Claims) JP 2003-213528 A (Claims)

  The present invention solves the above problems, and when used for electrode paste coating of PDP and other high-precision printing, when it is used for polyester monofilaments for precision screen wrinkles, CD printing and graphics, It is an object of the present invention to provide a polyester monofilament for high mesh screen wrinkles that does not cause coating defects.

In order to achieve the above object, the present invention provides a core-sheath-type composite polyester monofilament for screen wrinkles, wherein both the polymer constituting the core and the sheath are polyethylene terephthalate, and the solution viscosity (IV) of the core polymer Is 0.70 to 1.30, the breaking strength is 6.0 cN / dtex or more, and the number of knots having a composite cross-sectional wire diameter in the range of the following formula (1) is 1 piece / 1,000,000 m or less. Polyester monofilament for screen wrinkles.
1837 × {D / (10000 × π)} ^0.5 ≦ X ≦
2100 × {D / (10000 × π)} ^0.5 (1)
However, D: Fineness (dtex)
X: Combined cross-section wire diameter of knot yarn (μm)
And a core-sheath composite polyester monofilament, wherein the polymer constituting the core and the sheath is polyethylene terephthalate, and the sheath polymer has an inorganic content of 60% or more of the particle size of 0.50 μm or less. A polyester monofilament for a screen wrinkle characterized by containing 0.35 to 0.60% by weight of particles and having a breaking strength of 6.0 cN / dtex or more.

  The polyester monofilament for screen wrinkles of the present invention has an appropriate core polymer IV, break strength, number of knots, and appropriate break strength, content of inorganic particles contained in the sheath polymer, and particle size. The polyester monofilament for screen wrinkles, which has high precision weaving properties suitable for high precision printing such as PDP electrode paste coating, which was not possible with conventional monofilaments, excellent dimensional stability and scum suppression effect, and 355 mesh or more The polyester monofilament for high mesh screen wrinkles, which has a high mesh screen wrinkle weaving property, excellent dimensional stability and scum suppressing effect, and is suitable for high-precision printing such as CD printing and graphic printing.

Hereinafter, the present invention will be described in detail.
In addition, the polyester in this invention shows the polyethylene terephthalate (henceforth PET) whose repeating unit is ethylene terephthalate.

  In order to obtain high strength, screen filament monofilaments are generally spun so that the molecular orientation of the polymer forming the fiber is in a low orientation state, and after winding the unstretched yarn, it is stretched at a high magnification to achieve high orientation. It becomes. The highly oriented drawn yarn exhibits high strength, but becomes brittle with respect to bending, shearing, and scraping, and becomes more worn by wrinkles during weaving of a high-density screen. For this reason, in weaving high-density screen wrinkles, it is indispensable to obtain both high-quality screen wrinkles while maintaining filament strength and preventing scum generation.

  In the present invention, the polyester monofilament is a core-sheath type composite monofilament which is arranged so that the core part is covered with the sheath part in the cross section and the core part is not exposed on the fiber surface. By using a core-sheath type composite, it is possible to achieve both the strength required when weaving high-density screen wrinkles and the prevention of scum generation. Conventionally known. Here, the core-sheath type is not limited as long as the core part is completely covered by the sheath part, but in order to easily maintain the discharge stability during melt spinning and the dimensional stability of the screen after tensioning, It is preferable to arrange them concentrically. In addition, there are various cross-sectional shapes, such as round shape, flat shape, and square shape. However, it is easy to obtain stable yarn-making property and screen weaving property. In order to suppress the occurrence of halation, it is preferable to have a round cross section in view of the opening of the screen ridge, that is, the stability of the shape of the lattice-like space formed by the intersection of the warp yarn and the weft yarn.

  In the present invention, for example, in order to obtain a screen of 355 to 500 mesh (lines / 2.54 cm) for the purpose of printing with a high resolution and high precision as performed with a coating thickness of 10 μm or less, the single yarn fineness is 5 to 15 dtex. It is preferable that More preferably, it is 6 to 12 dtex.

  In the screen cocooning process, a tension of a certain value or more is required for dimensional stability of the cocoon, and the tension is determined by strength (cN / dtex) × mesh. In order to increase the density, it is generally sufficient to use a monofilament having a fineness. However, since the monofilament fineness and the mesh density are not completely inversely proportional, it is necessary to increase the breaking strength as the fineness is increased. For this reason, in the case of the monofilament of the present invention, the required breaking strength is 6.0 cN / dtex or more, more preferably 6.5 cN / dtex or more, and even more preferably 7.0 cN / dtex or more.

  The breaking elongation of the monofilament of the present invention is 15 to 25%. It suppresses the occurrence of weaving yarn breakage, scum generation, and component peeling, and improves dimensional stability. Preferably, the elongation at break is 17-22%.

In the present invention, when the fineness is D (dtex), the diameter of the knot yarn is X (μm) is 1837 × {D / (10000 × π)} ^{0.5 to} 2100 × {D / (10000 × π) } It is important that the number of knots in the range of ^0.5 is 1 / million m or less. Monofilaments containing knots exceeding the above range frequently cause uneven defects in the weave lattice spacing when screened, making them unsuitable for high-precision printing applications such as coating of PDP electrode paste. Preferably, the number of knots is 0.5 / million m or less, and more preferably 0 / million m. In addition, since the yarn diameter of the node yarn exceeds 2100 × {D / (10000 × π)} ^0.5 , it becomes a printing defect even in a screen wrinkle used for general printing. Of course, high precision printing applications should not be included. In this application, the wire diameter of the node yarn that causes the coating unevenness defect is 1837 × {D / (10000 × π)} ^0.5 or more.
In the present invention, when the IV of the core PET is excessively low, the strength of the monofilament is mainly handled by the core polymer, so that the strength characteristics cannot be satisfied. In addition, when IV is excessively high, when a stretching heat set for satisfying the above-mentioned strength characteristics is performed, not only uneven stretching of the core polymer is generated, but also heat degradation during melt spinning tends to proceed, In order to induce the generation of a gelled product, the uniformity in the longitudinal direction of the monofilament is inferior, and the above-defined knot yarn is frequently generated. Therefore, the core PET for satisfying the strength characteristics necessary for the monofilament, that is, the breaking strength of 6.0 cN / dtex or more, and obtaining good uniformity is preferably IV = 0.70-1.30, more preferably. Is IV = 1.00-1.20.

  The sheath PET in the present invention is preferably in the range of IV = 0.45 to 0.68, improves the composite stability and stretchability with the core PET, satisfies the breaking strength, and scum Generation is suppressed. More preferably, IV = 0.50-0.65.

  In high mesh screen knit weaving of 355 mesh or more, when the sheath PET contains 60% or more of the inorganic particles having a large particle diameter exceeding 0.50 μm, or the content is 0.60 wt. In the case where the ratio exceeds 1%, voids are likely to be formed on the fiber surface during monofilament melt spinning, and the uniformity of the fiber diameter and breaking strength in the longitudinal direction of the fiber is inferior, and the monofilament is abraded with a wing blade or the like. At this time, the fiber surface starts to be scraped off from the void portion appearing in a protruding shape on the fiber surface. In addition, when the inorganic particle content is less than 0.35% by weight or when inorganic particles are not included, the scratch resistance on the monofilament surface increases, so that the releasability from the warping creel is inferior, and the blade Scum occurs at each part of the weaving machine. Therefore, the sheath PET of the present invention contains 0.35 to 0.60% by weight of inorganic particles such as titanium oxide having a particle size of 60% or more and a particle size of 0.50 μm or less. To get enough. Preferably, the content is 0.40 to 0.50% by weight, and 70% or more of the content is a particle size of 0.50 μm or less. There is no particular limitation on the method for obtaining the target particle size of the inorganic particles in the polymer. For example, in the polymer polycondensation stage, the catalyst and titanium oxide are added separately to suppress aggregation. The method of doing is mentioned. About the content and particle size of the inorganic particle in this invention, it calculates | requires by the particle size distribution measured at 25 degreeC of constant temperature layers using LA-700 (PARTICLE SIZE ANALYZER) by HORIBA.

  The composite cross-sectional area ratio (core: sheath) of the core part PET and the sheath part PET in the present invention is obtained by taking a photograph with the cross section enlarged to an arbitrary magnification using a microscope, and using this photograph, the core part and the sheath part. The cross-sectional area ratio is determined and is preferably in the range of 70:30 to 90:10, which improves the breaking strength and the wear resistance during weaving. More preferably, the composite cross-sectional area ratio (core: sheath) is in the range of 75:25 to 85:15.

  In order to obtain the monofilament for a precision screen wrinkle of the present invention, the core polymer IV is as high as 0.70 to 1.30, and therefore, thermal degradation during melting proceeds directly to the generation of knots. For this reason, the polymer residence time from the core polymer extruder to the die can be obtained within 15 minutes. Preferably it is within 10 minutes, more preferably within 8 minutes. Here, the polymer residence time is a value obtained by gradually grading the polymer passage volume after the extruder such as an extruder, polymer piping, a pack member, and a die by a discharge amount (g / min).

  Manufacturing conditions other than the core polymer residence time are not particularly limited, but for the extrusion model, an extruder extruder that generally has a high polymer discharge property and a short polymer remaining time in a dead space is used. It is preferable. For the sheath polymer, the IV is a general-purpose level, so the contribution to the yarn is small. However, like the core polymer, the polymer residence time from the extruder to the die is preferably within 15 minutes, more preferably Is within 10 minutes, more preferably within 8 minutes. The spinning temperature and the melting temperature are preferably as low as possible in order to obtain the desired physical properties and are capable of stable spinning, in order to suppress thermal degradation of the polymer. The preferred spinning temperature is 290 to 300 ° C. is there. For polymer pipes and spin pack members, a static kneader such as a static mixer manufactured by Noritake Company may be installed in order to avoid pulverizing the generated polymer degradation products and revealing them as knots.

  For the yarn discharged from the die, when the core polymer IV is 1.00 or more, it is preferable to pass through a heating zone having an inner wall temperature of 300 to 340 ° C. immediately before cooling and solidification. Use of a heating zone having a distance of 4.5 cm and a length of 10 cm is preferable in terms of workability such as a wiping operation of a die and quality such as Wooster spots, and is intended to make it easy to obtain a desired strength and elongation.

  Although it does not specifically limit about the extending | stretching method of this invention, extending | stretching heat processing is carried out between 1st hot roller and 2nd hot roller according to IV of core part polymer to be used, and the strong elongation to obtain, 2nd A method of winding after relaxing between the hot roller and the cooling roller, first-stage stretching between the first hot roller and the second hot roller, and second-stage stretching heat treatment between the second hot roller and the third hot roller After that, it can be suitably selected from a method of winding after giving a relaxation between the third hot roller and the cooling roller, etc. About the direct spinning drawing method for directly drawing the undrawn yarn without winding it once. , Stretch spots are likely to occur, which is not preferable.

  The production conditions of the polyester monofilament for high mesh screens of the present invention are not particularly limited, but for the extrusion model, an extruder that generally has a high polymer discharge and a short polymer remaining time in a dead space. It is preferable to use an extruder. In addition, the spinning temperature and the melting temperature are intended to obtain the desired physical properties, and it is preferable to lower the temperature within a range where stable spinning is possible, in order to suppress thermal degradation of the polymer. The preferred spinning temperature is 290 to 300 ° C. is there. For the yarn discharged from the die, when the core polymer IV is 1.00 or more, it is preferable to pass through a heating zone having an inner wall temperature of 300 to 340 ° C. immediately before cooling and solidification. It is preferable to use a heating zone having a distance of 3.0 to 5.0 cm and a length of 10 to 20 cm in terms of workability such as wiping work of the die and quality such as Wooster spots, and to easily obtain the desired strength and elongation. belongs to.

  Although it does not specifically limit about the extending | stretching method of this invention, For example, the 1st hot roller whose surface temperature is 85-95 degreeC, and surface temperature depend on IV of the core polymer to be used and the strong elongation to obtain. Winding after stretching heat treatment at a draw ratio of 3.80 to 4.40 times between second hot rollers at 120 to 150 ° C., giving 0.5 to 3.0% relaxation between the second hot roller and the cooling roller The first step of stretching at a stretching ratio of 3.80 to 4.60 times between the first hot roller having a surface temperature of 85 to 95 ° C and the second hot roller having a surface temperature of 95 to 160 ° C, Subsequently, after the second heat treatment between the second hot roller and the third hot roller having a surface temperature of 150 to 230 ° C. at a draw ratio of 1.05 to 1.20 times, the second hot wire is drawn between the third hot roller and the cooling roller. It can be suitably selected from a method of winding after 0.5 to 6.5% of relaxation, etc., but for the direct spinning drawing method in which the undrawn yarn is drawn directly without being wound once, Is likely to occur and is not preferred.

Hereinafter, the present invention will be described in detail with reference to examples. The evaluation in the examples followed the following method.
1. Solution viscosity (IV)
It calculated from the value measured at 25 degreeC in orthochlorophenol.
2. Tensile strength at break The tensile strength was measured at an initial sample length of 20 cm and a tensile speed of 2 cm / min using a Tensilon tensile tester manufactured by Orientex.
3. Wire diameter uniformity (number of yarns)
Two ceramic guides with a surface roughness Rz of 0.8 μm or less are fixed in a slit shape, and using a gap gauge with a working accuracy of ± 1.0 μm, the fineness D of the monofilament to be evaluated is 2,080. * {D / (10,000 * (pi))} Prepare what adjusted the slit width to the width of ^0.5 . This is called a slab catcher. This slab catcher was installed on the yarn path of the production time, the monofilament was allowed to pass simultaneously with the production, the number caught on the slit was counted, and converted to the number per million meters. When the number of knots was less than 0.6 / 1,000,000 m, ○, 0.6 to 1 million / m, Δ, and more than 1 / 1,000,000 m, x, and ○ and Δ passed.
4). Particle size distribution The monofilament to be evaluated was dissolved, and measured using a HORIBA LA-700 (PARTICLE SIZE ANALYZER) at a constant temperature of 25 ° C. The particle size distribution (%) in the examples was 0.50 μm. The ratio of the following particles to the total content is shown.
5). Weaving lattice defects Using a Sruzer type weaving machine, weave 10 anti-weaving screen fabrics with a vertical and horizontal density of 350 mesh (350 pieces / 2.54 cm), a rotational speed of 350 rpm and a weaving width of 2.54 m and a length of 30 m. For a woven lattice formed of warp and weft yarns in the woven fabric, a portion having a lattice interval of 1.5 times or more than the normal portion, for example, a yarn having a fineness of 10.0 decitex, that is, a fine diameter of 30 μm is used. In the case of the 350 mesh screen fabric, a lattice having a spacing of 64 μm or more with respect to a normal portion lattice spacing of 42 μm was regarded as a lattice defect, and a lattice defect having a lattice defect number of 1 piece or more was rejected.
6). Scum suppression effect Through a through-weaving machine, weaving a 350-500 mesh screen fabric in 15 anti-continuations, until the knot stain progressed and normal weaving could not be maintained, and we had to stop. In the case of 350 mesh weaving, ○ exceeding 340 m, Δ 250-340 m, × less than 250 m, ○ and Δ passing, and 355 mesh to 500 mesh weaving Is over 200 m, ○ is 150-200 m, Δ is less than 150 m, and ○ and Δ are acceptable.
7). Dimensional stability of the screen Observe the distortion of the printed pattern, and in the cumulative number of printed sheets at the time of the distortion, ○ over 1,500, Δ over 1,200-1,500, x over 1200, ○ and Δ pass. It was.

Example 1
Using a composite spinning machine consisting of an extruder extruder with a single flight screw φ25 manufactured by Tsunasho made in Japan, IV = 0.4% PET containing IV = 1.00 in the core and 0.5% by weight of titanium oxide particles in the sheath Using 0.51 PET, the polymer discharge amount was adjusted so that the composite cross-sectional area ratio would be 80:20, using a polymer pipe such that the residence time required from the core component extruder to the die discharge was 10 minutes. After adjusting and discharging the yarn from the die at a spinning temperature of 298 ° C., after passing through a heating zone having an inner wall temperature of 300 ° C. and a distance of 4.5 cm and a length of 10 cm, with cooling air The core-sheath type composite monofilament yarn which had been cooled and solidified was once wound up with an unstretched yarn at a spinning speed of 850 m / min after applying the oil.

  This undrawn yarn is 4.39 times between the first hot roller having a surface temperature of 90 ° C. and the second hot roller having a surface temperature of 100 ° C., and 1.between the second hot roller and the third hot roller having a surface temperature of 200 ° C. 07 times, 4.29% relaxation was applied between the third hot roller and the cooling roller having a surface temperature of room temperature, and the stretched heat setting was performed to obtain a composite monofilament 1.0 kg wound bobbin package having a fineness of 10.0 dtex. .

  The resulting monofilament had a breaking strength of 7.1 cN / dtex and a breaking elongation of 19.5%. When the slab catcher is installed on the unwinding yarn path of the warp machine and the warp is performed using 500 monofilaments, the number of knots is 0.6 / 1,000,000m, and the desired wire diameter is uniform. It was sex. In addition, as a result of weaving a 350 mesh screen wrinkle using the monofilament, the weaving lattice defect was 0.6 pieces / reverse, and the weaving length until stoppage due to wrinkle contamination was 450 m. Printing using the screen wrinkle As a result, pattern distortion did not occur up to 1700 printed sheets, and a good scum suppressing effect and dimensional stability were obtained. In addition, the screen electrode was used to apply the electrode paste of PDP, and coating unevenness was confirmed, but this did not lead to image defects.

Example 2
Using a PET of IV = 0.78 for the core and the same sheath as in Example 1, adjusting the polymer discharge amount so that the composite cross-sectional area ratio is 80:20, and discharging the die from the core component extruder The core sheath was cooled and solidified with cooling air after discharging the yarn from the die at a spinning temperature of 295 ° C., using a polymer pipe that required a residence time of 8 minutes. The unstretched yarn was once wound up at a spinning speed of 1200 m / min after applying the oil agent to the mold composite monofilament yarn.

  This undrawn yarn is 3.98 times between the first hot roller having a surface temperature of 90 ° C. and the second hot roller having a surface temperature of 130 ° C., and 1.35% between the second hot roller and the cooling roller having a surface temperature of room temperature. A relaxed and stretched heat set was performed to obtain a composite monofilament 1.0 kg wound bobbin package having a fineness of 10.0 dtex.

The resulting monofilament had a breaking strength of 6.2 cN / dtex and a breaking elongation of 21.0%. When a slab catcher is installed on the unwinding yarn path of the warp machine and the warp is made using 500 monofilaments, the number of knots is 0.5 / 1,000,000m, and the wire diameter is uniform. It was sex. In addition, the result of weaving a 350 mesh screen hoe using the monofilament showed that the woven lattice defect was 0.4 pieces / reverse, and the weaving length until stoppage due to scum stain was 500 m, and printing using the screen hoe was performed. As a result, there was no pattern distortion up to 1318 printed sheets, and a screen wrinkle having a good scum suppressing effect, dimensional stability and quality was obtained.
Moreover, the electrode pad application | coating of PDP was performed using this screen cage | basket, and the coating nonuniformity was confirmed, but there was no coating nonuniformity generation | occurrence | production.

Example 3
A fineness of 10 was obtained in the same manner as in Example 1 except that PET having IV = 1.30 was used for the core and PET having IV = 0.65 containing 0.50% by weight of titanium oxide particles was used for the sheath. A 0 dtex complex monofilament 1.0 kg wound bobbin package was obtained. The breaking strength of the obtained monofilament was 8.1 cN / dtex and the elongation at break was 15.3%. When a slab catcher is installed on the unwinding yarn path of a warp machine and the warp is performed using 500 monofilaments, the number of knots is 1.0 / 1,000,000 m, and is used for precision printing. The wire diameter uniformity was satisfactory. Further, in the results of weaving a 350 mesh screen hoe using the monofilament, the woven lattice defect was 0.9 pieces / reverse, and the weaving length until the stoppage due to scum stain was 260 m, and printing using the screen hoe was performed. As a result, there was no distortion of the pattern up to 1850 printed sheets, there was no problem in suppressing scum, and a screen wrinkle having good dimensional stability was obtained. Also, PDP electrode paste application was performed and application unevenness was confirmed, but it was not at a level leading to image defects.

Example 4
Using PET of IV = 0.70 in the core and PET of IV = 0.45 containing 0.50% by weight of titanium oxide particles in the sheath, the residence time required from the core component extruder to the die discharge is 10 A composite monofilament 1.0 kg wound bobbin package having a fineness of 10.0 dtex was obtained in the same manner as in Example 2 except that polymer pipes were used. The resulting monofilament had a breaking strength of 6.0 cN / dtex and a breaking elongation of 17.7%. When the slab catcher is installed on the unwinding yarn path of the warp machine and the warp is performed using 500 monofilaments, the number of knots is 0.2 / 1,000,000m, and the wire diameter is uniform. It was sex. Further, in the results of weaving a 350 mesh screen hoe using the monofilament, the woven lattice defect was 0.1 pieces / reverse, and the weaving length until the stoppage due to scum stain was 340 m, and printing using the screen hoe was performed. As a result, there was no pattern distortion up to 1290 printed sheets, and there was no problem in the scum suppressing effect and dimensional stability, and a screen flaw having both quality was obtained. Moreover, the electrode pad application | coating of PDP was performed using this screen cage | basket, and the coating nonuniformity was confirmed, but there was no coating nonuniformity generation | occurrence | production.
The results are summarized in Table 1.

Comparative Example 1
A composite monofilament 1.0 kg wound bobbin package with a fineness of 10.0 dtex was obtained in the same manner as in Example 1 except that PET with IV = 1.40 was used for the core. The resulting monofilament had a breaking strength of 8.5 cN / dtex, a breaking elongation of 16.5%, a number of knots of 2.2 pieces / 1,000,000 m, and the result of weaving a 350 mesh screen koji was The weaving length up to the stop is 280 m, and the printed result does not cause distortion of the pattern up to 1920 printed sheets, and there is no problem in scum suppression effect and dimensional stability, but the number of knots when warping is 2.2. Piece / million m, and the woven lattice defect was inferior to 2.1 pieces / anti. As a result of microscopic FT-IR analysis of the node part, it was found that a large amount of gelled product due to excessively high IV of the core part PET was mixed. Moreover, when the electrode paste application of PDP was performed using the screen cage and the coating irregularity was confirmed, the electrode irregularity that seems to be due to the woven lattice defect of the screen cage occurred and cannot be used for PDP. there were.

Comparative Example 2
Spinning temperature using a polymer pipe with a residence time of 6 minutes from the extruder to the die discharge using only PET of IV = 0.65 containing 0.50% by weight of titanium oxide particles. After discharging the yarn from the die at 290 ° C, the single-component monofilament yarn cooled and solidified with cooling air without passing through the heating zone is wound once with unstretched yarn at a spinning speed of 800 m / min after applying the oil. Then, after stretching in the same manner as in Example 2, a 1.0 kg monofilament bobbin package having a fineness of 10.0 dtex was obtained.

  The monofilament obtained had a breaking strength of 5.4 cN / dtex, a breaking elongation of 24.0%, a number of knots of 0.1 / 1,000,000 m, and the number of knots at the time of warping was 0.1. / 1 million m, and there are no problems with woven lattice defects of 0.1 pieces / reverse, but the results of weaving of 350 mesh screen reeds showed that scum and thread breakage occurred frequently, and the weaving length until stopping was 120 m and 350 mesh It was not able to withstand weaving. As a result of printing, pattern distortion occurred when the number of printed sheets was 980, and a screen wrinkle of a level that could be used for actual precision printing was not obtained.

Comparative Example 3
A composite monofilament 1.0 kg wound bobbin with a fineness of 10.0 dtex in the same manner as in Example 2 except that polymer piping is used so that the residence time required from the core component extruder to the die discharge is 20 minutes. Got the package. The monofilament obtained had a breaking strength of 6.2 cN / dtex, a breaking elongation of 20.8%, a number of knots of 3.5 pieces / 1,000,000 m. The print result shows that there is no pattern distortion up to 1300 printed sheets, and there is no problem with the scum suppression effect and dimensional stability, but the number of knots at the time of warping is 3.5 / million m. Thus, the woven lattice defect was extremely inferior to 3.3 pieces / counter, and a screen wrinkle of a level that could be used for practical precision printing was not obtained. As a result of the microscopic FT-IR analysis of the knot portion, it was found that a large amount of gelled product was mixed due to excessive residence time of the core portion PET during spinning of IV. Moreover, when the electrode paste application | coating of PDP was performed using this screen wrinkle and application | coating unevenness was confirmed, the electrode unevenness considered to be the fluctuation | variation of the textile lattice spacing of a screen wrinkle has generate | occur | produced, and cannot be used for PDP. It was a thing.

Comparative Example 4
Spinning temperature using a polymer pipe that uses only PET of IV = 0.78 containing 0.50% by weight of titanium oxide particles as a single component and requires a residence time of 6 minutes from the extruder to the die discharge. After discharging the yarn from the base at 295 ° C., the single component monofilament yarn cooled and solidified with cooling air without passing through the heating zone is wound once with unstretched yarn at a spinning speed of 800 m / min after applying the oil. The film was stretched in the same manner as in Example 2 except that it was stretched and heat set at 4.50 times between the first hot roller having a surface temperature of 90 ° C. and the second hot roller having a surface temperature of 130 ° C., and the fineness was 10. A 0-dtex monofilament 1.0 kg wound bobbin package was obtained. The monofilament obtained had a breaking strength of 6.0 cN / dtex, a breaking elongation of 26.1%, a number of knots of 0.2 / 1,000,000 m, and 0.1 woven lattice defects at the time of warping. / On the other hand, pattern distortion does not occur up to 1260 printed sheets, and there is no problem, but a large amount of scum is generated in the weaving result, the weaving length to the stop is 120 m, and it is not at a level that can produce a screen mesh of 350 mesh. .

実施例５
鞘部ポリマーに含有量の７０％以上が０．５０μｍ以下である酸化チタン粒子を０．５０重量％含有したＩＶ＝０．５１のＰＥＴを用い、ポリマー吐出量を変更したこと以外、実施例１と同様の方法で繊度が１２．０デシテックスの複合モノフィラメント１．０ｋｇ巻きボビンパッケージを得た。

Example 5
Example 1 except that PET of IV = 0.51 containing 0.50% by weight of titanium oxide particles having a content of 70% or more of 0.50 μm or less in the sheath polymer was used and the polymer discharge rate was changed. A composite monofilament 1.0 kg wound bobbin package having a fineness of 12.0 dtex was obtained in the same manner as above.

  The resulting monofilament had a breaking strength of 7.1 cN / dtex and a breaking elongation of 20.5%. As a result of weaving a 355 mesh high-mesh screen wrinkle using the monofilament, the weaving length up to the stoppage due to wrinkle dirt is 300 m. As a result of printing using the screen wrinkle, up to 1710 printed patterns No distortion occurred and good scum suppression effect and dimensional stability were obtained. In addition, as a result of observing the scum adhering to the cocoon blades after weaving with an electron microscope, the scum was in a powder form and was woven into the screen cocoon product and did not cause a defect.

Example 6
A composite monofilament having a fineness of 10.0 dtex was obtained in the same manner as in Example 5 except that the titanium oxide content of the sheath polymer was 0.35% by weight and the polymer discharge rate was changed. As a result of weaving a 380 mesh high mesh screen wrinkle using the monofilament, the weaving length up to the stoppage due to wrinkle stains is 180 m, and as a result of printing using the screen wrinkle, a pattern up to 1680 sheets can be printed. No distortion occurred and no scum-inhibiting effect and good dimensional stability were obtained.

Example 7
Using PET of IV = 0.78 in the core polymer, and PET of IV = 0.51 containing 0.45% by weight of titanium oxide particles having a content of 60% or more and 0.50 μm or less in the sheath polymer. After discharging the yarn from the die at a spinning temperature of 295 ° C., the core-sheath type composite monofilament yarn cooled and solidified with cooling air was once wound up with an unstretched yarn at a spinning speed of 1200 m / min after applying the oil.

  This undrawn yarn is 4.04 times between the first hot roller having a surface temperature of 90 ° C. and the second hot roller having a surface temperature of 130 ° C., and 1.35% between the second hot roller and the cooling roller having a surface temperature of room temperature. Was applied with stretching and heat setting was performed to obtain a composite monofilament 1.0 kg wound bobbin package having a fineness of 8.0 dtex.

  The resulting monofilament had a breaking strength of 6.2 cN / dtex and a breaking elongation of 22.0%. As a result of weaving a 420-mesh high mesh screen using this monofilament, the weaving length to the stoppage due to wrinkles is 270 m, and as a result of printing using this screen, up to 1320 printed patterns No distortion occurred, and a good scum-inhibiting effect and dimensional stability without problems as a precision printing screen wrinkle were obtained.

Example 8
A composite monofilament was obtained in the same manner as in Example 7 except that the sheath polymer was PET having IV = 0.67. As a result of weaving a 420 mesh high mesh screen using the monofilament, a fibrous scum was generated in the blade, but the weaving length to the stoppage due to the dust was 160 m, and the screen was used. As a result of printing, pattern distortion did not occur up to 1250 printed sheets, and a scum suppressing effect and dimensional stability, which were no problem for a precision printing screen wrinkle, were obtained.

Example 9
The core polymer is a PET with IV = 1.30, and the sheath polymer is a PET with IV = 0.67 containing 0.55% by weight of titanium oxide particles whose content is 65% or more and 0.50 μm or less. A composite monofilament having a fineness of 6.0 dtex was obtained in the same manner as in Example 5 except that the polymer discharge amount was changed. As a result of weaving a 500 mesh high mesh screen using this monofilament, the weaving length to the stoppage due to the scum is 155 m. As a result of printing using this screen, up to 1840 printed patterns No distortion occurred, and a scum-inhibiting effect and good dimensional stability, which were no problem for a precision printing screen wrinkle, were obtained.

Comparative Example 5
A composite monofilament was obtained in the same manner as in Example 5 except that the content of titanium oxide in the sheath polymer was 0.20% by weight. As a result of weaving a 355 mesh high mesh screen wrinkle using the monofilament, unraveling failure due to ring slippage at the bobbin package taper portion during warp aging and weft breakage during weaving occurred, The scum generated in the scum was remarkable, and the weaving length until the stoppage due to the scum was 110 m, which made it difficult to industrially produce a screen sledge for precision printing. In addition, as a result of printing using the screen wrinkle, pattern distortion did not occur up to 1600 printed sheets, and there was no problem in dimensional stability.

Comparative Example 6
A composite monofilament was obtained in the same manner as in Example 5 except that the content of titanium oxide in the sheath polymer was 0.80% by weight. As a result of weaving a 355 mesh high mesh screen using this monofilament, scum generation at the reed blades was significant, and the weaving length until stopping due to reed contamination was 100 m. A large amount of titanium oxide agglomerates obtained by collecting scum after weaving and observing with an electron microscope and elemental analysis were confirmed, making it difficult to industrially produce precision printing screens. In addition, as a result of printing using the screen ridge, pattern distortion did not occur up to 1660 printed sheets, and dimensional stability was not a problem.

Comparative Example 7
From an extruder extruder with a screw outer diameter of φ25 mm manufactured by Nippon Steel, using PET of IV = 0.78 containing 0.55% by weight of titanium oxide particles having a content of 60% or more of 0.50 μm or less. Using a single-component spinning machine, the core-sheath type composite monofilament yarn discharged from the die at a spinning temperature of 295 ° C. and then cooled and solidified with cooling air was applied at a spinning speed of 900 m / min after applying the oil. The drawn yarn was wound up once.

  This unstretched yarn was drawn and heat set at 3.80 times between a first hot roller having a surface temperature of 90 ° C. and a second hot roller having a surface temperature of 130 ° C., and wound with 1.0 kg of a composite monofilament having a fineness of 12.0 dtex Got the bobbin package.

  The breaking strength of the obtained monofilament was 5.5 cN / dtex, and the breaking elongation was 28.6%. As a result of weaving a 355 mesh high mesh screen wrinkle using the monofilament, the weaving length up to the stoppage due to wrinkle stains is 120 m. As a result of printing using the screen wrinkle, 930 prints Distortion occurred and was not industrially usable for precision printing.

Comparative Example 8
A composite monofilament was obtained in the same manner as in Example 7 except that PET containing 0.50% by weight of titanium oxide particles having a content of 30% in the sheath polymer of 0.50 μm or less was used. As a result of weaving a 355 mesh high-mesh screen wrinkle using the monofilament, unraveling failure due to warp threading at the warp knitting and scraping thread breakage at the creel guide part, and occurrence of weft breakage during weaving are remarkable. The generation of scum at the wing blade portion was remarkable, and the weaving length until the stoppage due to 筬 dirt was 80 m, making it difficult to industrially produce screen ridges for precision printing.

Comparative Example 9
A composite monofilament was obtained in the same manner as in Example 7, except that the sheath polymer was 7.0 mol% polyethylene PET having IV = 0.64. The resulting monofilament had a breaking strength of 6.1 cN / dtex and a breaking elongation of 23.1%. As a result of weaving a 355 mesh high mesh screen wrinkle using the monofilament, the fibrous shape at the blade portion was obtained. The occurrence of scum became remarkable, and the weaving length until the stoppage due to fouling was 105 m. In addition, as a result of printing using the screen wrinkle, pattern distortion did not occur up to 1300 printed sheets, but many fibrous scum defects were found in the screen wrinkles, and many printing defects due to coating unevenness were found. However, it could not be used for precision printing.

Claims (5)

A core-sheath-type polyester monofilament for screen wrinkles, the polymer constituting the core and the sheath are both polyethylene terephthalate, and the solution viscosity (IV) of the core polymer is 0.70 to 1.30, A polyester monofilament for screen wrinkles, characterized in that the breaking strength is 6.0 cN / dtex or more and the number of knots having a composite cross-sectional wire diameter in the range of the following formula (1) is 1 piece / 1,000,000 m or less.
1837 × {D / (10000 × π)} ^0.5 ≦ X ≦
2100 × {D / (10000 × π)} ^0.5 (1)
However, D: Fineness (dtex)
X: Combined cross-section wire diameter of knot yarn (μm)   A core-sheath-type composite polyester monofilament, wherein both the polymer constituting the core and the sheath are polyethylene terephthalate, and the sheath polymer contains inorganic particles having a particle size of 0.50 μm or less of 60% or more. A polyester monofilament for screen wrinkles characterized by containing 0.35 to 0.60% by weight and having a breaking strength of 6.0 cN / dtex or more.   The polyester monofilament for a screen bag according to claim 2, wherein the polyethylene terephthalate of the core part has IV = 0.70-1.30.   The composite cross-sectional area ratio (core: sheath) of the core part and the sheath part is 70:30 to 90:10, and the solution viscosity (IV) of the sheath polymer is 0.45 to 0.68. The polyester monofilament for screen wrinkles according to any one of claims 1 to 3.   The polyester monofilament for screen wrinkles according to any one of claims 1 to 4, wherein the elongation at break is 15 to 25%.