JP7045297B2 - Monofilament for screen gauze and its manufacturing method - Google Patents

Description

The present invention relates to a monofilament for screen gauze and a method for manufacturing the same.

As the screen gauze for printing, a gauze woven material made of polyester or polyamide is often used at present from the viewpoint of strength, dimensional stability and the like (see, for example, Patent Documents 1 and 2). In particular, polyester gauze fabric is widely used because it has excellent dimensional stability and is suitable for printing in fields where high precision printing is required.
However, although Patent Document 1 describes a monofilament for screen gauze in which the core is polyester and the sheath is polyester containing a specific organic pigment, the strength or elongation is not sufficient, and pan sink marks occur or the eyes are printed during weaving. There are problems such as misalignment and scum, and printing durability. Further, Patent Document 2 describes a polyamide monofilament that can be used for screen printing, but in the case of a polyamide-only monofilament, dimensional stability is inferior and precision printing is difficult.
As a method for solving these problems, for example, in Patent Document 3, a core having improved dimensional stability, adhesiveness to a photosensitive resin, reed scraping resistance, etc. by arranging polyester in the core and polyamide in the sheath. A monofilament made of a sheath composite fiber is disclosed. Patent Document 4 discloses a polyester single monofilament made of a modified polyester obtained by copolymerizing 1 to 15% by mass of a glycol component having a molecular weight of 300 to 6000.

Japanese Patent No. 4661501 Japanese Unexamined Patent Publication No. 2005-256197 Japanese Patent No. 2597111 Japanese Patent No. 2682065

However, the monofilament in which polyester is arranged in the core and polyamide is arranged in the sheath as described in Patent Document 3 has better dimensional stability and adhesiveness to the photosensitive resin than the conventional ones, but during weaving and screens. When an impact is applied to the filament, such as during printing after it has been made into a gauze, the polyamide of the sheath is easily peeled off, so that scum is likely to occur and halation is also likely to occur, and the quality of the screen gauze deteriorates. The copolymerized polyester single monofilament as described in Patent Document 4 is less likely to cause misalignment and scum, and has good reed wear resistance, but is prone to halation and has low dimensional stability, so that it has a high resolution. Precise printing is difficult. Further, since the strength is low, there is a problem that the printing durability is low.

Therefore, the present invention solves the above-mentioned problems, and in a monofilament for screen gauze in which polyester is arranged on the core and the sheath, peeling of the core sheath, scum and pan sink marks are reduced, dimensional stability is good, halation is suppressed, and printing is performed. The purpose is to obtain a high-quality monofilament for screen gauze with excellent durability.

The present inventor has specified the core-sheath ratio and the matting agent concentration of the monofilament in a monofilament for screen gauze in which a specific homopolyethylene terephthalate is arranged in the core and a specific polyethylene glycol is arranged in the sheath, and the present invention is performed at the drawing stage after spinning. By relaxing in a specific range, a monofilament with a specific breaking strength, breaking elongation, 5% modulus, and 10% modulus reduces pan sink marks, core sheath peeling, and scum, and provides dimensional stability. It has been found that it is possible to obtain a high-quality screen gauze that is good, suppresses halation, and has excellent printing durability.
That is, the first aspect of the present invention is a core-sheath monofilament for screen gauze, wherein the core component is polyester and the sheath component is a copolymerized polyester core-sheath monofilament, which satisfies the following (1) to (8). It is a summary.
(1) The resin of the core component has an intrinsic viscosity (IV) of 0.7 to 1.0 dl / g. Homo polyethylene terephthalate (2) The resin of the sheath component has an intrinsic viscosity (IV) of 0.55 to 0. Modified polyethylene terephthalate copolymerized with polyethylene glycol having a viscosity of .68 dl / g (3) Core-sheath ratio (area ratio) is 65:35 to 90:10.
(4) Breaking strength is 6.2 to 7.5 cN / dtex
(5) Elongation at break is 20-28%
(6) 5% modulus is 3 to 4.5 cN / dtex
(7) 10% modulus is 5-7cN / dtex
(8) The concentration of the matting agent of the core component is 0.05 to 0.5% by mass, and the concentration of the matting agent of the sheath component is 0.2 to 0.5% by mass.
The second gist is that the monofilament for screen screens is obtained by stretching and relaxing treatment.
Further, the third gist is that the monofilament for screen gauze does not break when the number of times of up and down is 30,000 or more in the wear test under the following conditions.
Condition: Pass one fixed monofilament in the direction perpendicular to the reed. The threaded monofilament is tilted 5 ° in the vertical direction with respect to the reed, and the end is fixed with a weight of 1 g / d. Move the reed up and down (1 round trip = 1 count) on the monofilament. The average number of times the monofilament is cut at this time is counted.
Then, homopolyethylene terephthalate having an intrinsic viscosity (IV) of 0.7 to 1.0 dl / g is used as a core component, and polyethylene glycol having an intrinsic viscosity (IV) of 0.55 to 0.68 dl / g is copolymerized. A method for producing a monofilament for screen gauze, which is obtained by spinning the modified polyethylene terephthalate as a sheath component and then stretching it from a spinneret. The fourth gist is a method for producing a core-sheath monofilament.

According to the monofilament for screen gauze of the present invention, peeling of the core sheath and generation of scum are reduced, and when used for screen gauze, dimensional stability is good, halation is suppressed, and printing durability is improved. ..

Hereinafter, the present invention will be described in detail.

The monofilament for screen gauze of the present invention is a core-sheath monofilament in which the sheath component is a copolymerized polyester containing polyethylene glycol and the core component is polyester.

Homopolyethylene terephthalate (PET) is used as the polyester constituting the core component in the present invention. The intrinsic viscosity (IV) of PET is 0.7 to 1.0 dl / g, preferably 0.72 to 0.9 dl / g. When the intrinsic viscosity (IV) is less than 0.7 dl / g, the fiber strength tends to be low and the tear strength of the woven fabric tends to be low. Further, from the viewpoint of silk-reeling property, scum, printing durability, and cost, it is preferably 1.0 dl / g or less.

The matting agent concentration of PET constituting the core component in the present invention is preferably 0.05 to 0.5% by mass.
The matting agent in the present invention suppresses the transmission and reflection of light and suppresses the glare of fibers, and examples thereof include inorganic particles such as titanium oxide, zinc oxide, and calcium carbonate. Titanium oxide is preferable from the viewpoint of cost and ultraviolet absorption.

The copolymerized polyester constituting the sheath component in the present invention is a modified polyethylene terephthalate in which polyethylene glycol is copolymerized. Polyethylene glycol preferably has a molecular weight of 300 to 6000, and more preferably 400 to 1000. If the molecular weight is less than 300, the boiling point of polyethylene glycol is low, so that polyethylene glycol is scattered outside the reaction system during the polycondensation reaction, and it is difficult to obtain a constant amount of copolymerization. On the contrary, polyethylene glycol having a molecular weight of more than 6000 tends to deteriorate the oxidative decomposition resistance of the copolymerized polymer and it is difficult for polyethylene glycol to be uniformly copolymerized.
The copolymerization amount of polyethylene glycol is preferably 1 to 12% by mass, more preferably 2 to 10% by mass, based on polyester. 1% or more is preferable from the viewpoint of suppressing the generation of scum and maintaining good adhesion to the photosensitive resin. From the viewpoint of maintaining good tension and waist of the screen gauze, 12% by mass or less is preferable. The glass transition temperature of the copolymerized polyester is preferably 45 to 68 ° C., and it is preferable to appropriately adjust the molecular weight and the copolymerization amount of polyethylene glycol within such a range. When the glass transition temperature is 45 ° C or higher, the glass transition point is usually higher than room temperature, so that the dimensional stability of the gauze is good, and when it is 68 ° C or lower, the cause of scum generation is reduced. It is preferable from the viewpoint of maintaining good adhesion to the photosensitive resin.
Further, as other copolymerization components, a dioxy compound such as hexamethylene glycol, adipic acid, isophthalic acid, sulfoisophthalic acid, dicarboxylic acid such as phthalic acid, bisphenol A and the like may be copolymerized. From the viewpoint that the above-mentioned effect can be easily obtained, it is particularly preferable that the polyethylene glycol is substantially copolymerized with the above-mentioned polyethylene glycol.

The intrinsic viscosity (IV) of the copolymerized polyester constituting the sheath component in the present invention is 0.55 to 0.68 dl from the viewpoints that the quality of the yarn or mesh can be easily maintained, the strength can be easily obtained, and the spinnability is good. / G is preferable, and more preferably 0.6 to 0.65 dl / g.

The concentration of the matting agent (matting agent concentration) of the copolymerized polyester constituting the sheath component in the present invention is preferably 0.2 to 0.5% by mass. If the matting agent concentration is less than 0.2% by mass, halation is likely to occur during resin exposure in screen printing, and if it exceeds 0.5% by mass, traveler scraping may occur during drawing of undrawn yarn. Reed scraping is likely to occur during weaving.

The concentration of the matting agent (the concentration of the matting agent) in the entire monofilament for screen gauze of the present invention is preferably 0.2 to 0.5% by mass. If the matting agent concentration is less than 0.2% by mass, halation is likely to occur when the resin is exposed to light in screen printing, and if it exceeds 0.5% by mass, traveler scraping occurs when the undrawn yarn is drawn. And reed scraping during weaving is likely to occur.

The polyester used in the present invention contains carbon black, pigments, dyes, antistatic agents, antistatic agents, and light-resistant materials as long as it does not interfere with spinning and stretching operability, weaving properties, etc., as long as the effects of the present invention are not impaired. Additives such as agents may be added and used.

The ratio (area ratio) of the core component and the sheath component of the monofilament for screen gauze of the present invention, that is, the core-sheath ratio is 65:35 from the viewpoint of maintaining good filament strength and resistance to wear due to reeds during weaving. It is preferably from 90:10, particularly preferably from 75:25 to 85:15. When the sheath component exceeds 35%, it is difficult to maintain the breaking strength and the breaking elongation, and the printing durability of the screen gauze tends to decrease. When the sheath component is less than 10%, the monofilament tends to be scraped by a reed or the like during weaving, misalignment occurs, and the adhesiveness with the photosensitive resin during screen printing tends to decrease.

The cross-sectional shape of the monofilament for screen gauze of the present invention is not particularly limited, but the outer shape of the fiber is preferably circular. Further, it is preferable that the core component is not exposed to the surface layer of the filament. From the viewpoint of the dimensional stability of the screen after the gauze, the shape and arrangement of the core component are preferably arranged concentrically with the sheath component to form a single circle.

The fineness of the monofilament for screen gauze of the present invention is preferably 4 to 30 dtex. From the viewpoint of high-precision precision printing, 30 dtex or less is preferable.

The breaking strength of the monofilament for screen gauze of the present invention is 6.2 to 7.5 cN / dtex, more preferably 6.4 to 7.2 cN / dtex, from the viewpoint of the gauze property and printing durability of the screen gauze. Is. When the breaking strength is less than 6.2 cN / dtex, the printing durability tends to decrease. When the breaking strength exceeds 7.5 cN / dtex, the breaking elongation tends to be less than 20%, and in this case, reed scraping and scum occur during weaving, and the weaving property and the gauze property of the screen gauze tend to decrease. ..

The breaking elongation of the monofilament for screen gauze of the present invention is 20 to 28%. More preferably, it is 23 to 28%. When the breaking elongation of the monofilament for screen gauze of the present invention is less than 20%, reeds are scraped during weaving, scum is generated, and weaving property and gauze property are deteriorated. When the elongation at break exceeds 28%, the amorphous portion of the filament increases, so that the dimensional stability of the screen gauze tends to deteriorate, and the printing durability deteriorates.

The 5% modulus of the monofilament for screen screens of the present invention is 3 to 4.5 cN / dtex, preferably 3.2 to 4 cN / dtex. The 5% modulus is preferably high from the viewpoint of the printing durability of the screen gauze, but if it exceeds 4.5 cN / dtex, scraping due to the reed is likely to occur during weaving, and pan sink marks are observed. Screen gauze using this cannot be obtained with good quality due to defects such as weaving of generated scrapes and the inclusion of vertical and horizontal streaks. If it is less than 3 cN / dtex, the dimensional stability of the screen gauze is deteriorated at the time of screen printing, misalignment occurs, printing defects occur, and printing durability is lowered.

The 10% modulus of the monofilament for screen screens of the present invention is 5 to 7 cN / dtex, preferably 5.2 to 6.2 cN / dtex. Generally, the elongation rate of the screen gauze at the time of gauze or printing is around 10%, so that the 10% modulus is kept high from the viewpoint of dimensional stability at the time of gauze. However, when the monofilament for screen gauze of the present invention exceeds 7 cN / dtex, it induces fibrilization due to high molecular orientation of the monofilament, and induces scum generation on the surface of the monofilament during weaving and repeated printing. , Printing performance deteriorates. If it is less than 5 cN / dtex, misalignment or the like is likely to be induced, and in the case of high-precision printing, the printing performance is deteriorated.

The monofilament for screen gauze of the present invention is preferably one that has been stretched and relaxed.

The hot water shrinkage rate of the monofilament for screen screen of the present invention is preferably 3 to 9%. More preferably, it is 5 to 8.5%. The hot water shrinkage rate is preferably lowered from the viewpoint of the dimensional stability of the screen gauze. If it exceeds 9%, the dimensional stability at the time of screen printing tends to deteriorate, so that precise printing tends to be impossible. The lower limit is preferably about 3% because the heating roller and the stretching equipment are special.

The number of times until the monofilament for screen gauze of the present invention is broken (number of breaks) in the reed wear test described later is preferably 30,000 times or more. When the number of breaks is less than 30,000, scum and reed scraping generated during weaving tend to be woven together into the screen gauze and defects are likely to occur.
Reeds are usually for 310-460 mesh / inch with a fiber diameter of 27-30 μm, for 200-380 mesh / inch with a fiber diameter of 33-45 μm, and for 60-225 mesh / inch with a fiber diameter of 48-54 μm. You should select and use the one.

When the screen gauze using a monofilament is exposed to light, if the average reflectance is not sufficient at a wavelength of 300 to 500 nm, a part where the photosensitive resin is solidified and a part where the photosensitive resin is not solidified occur, so-called halation occurs, and normal photosensitization treatment cannot be performed. Therefore, the printing performance is deteriorated and the image at the time of printing is blurred. It is preferable that the monofilament for screen gauze of the present invention does not cause such halation even when it is made into an undyed gauze fabric. For this purpose, for example, it is preferable that the amounts of the core component, the sheath component, and the monofilament matting agent of the monofilament for screen gauze of the present invention are in the above range. To give a specific example in a suitable range, the concentration of the matting agent of the core component is 0.05 to 0.5% by mass, and the concentration of the matting agent of the sheath component is 0.2 to 0.5% by mass. It is mentioned that the concentration of the matting agent of the monofilament is 0.2 to 0.5% by mass. As described above, by containing 0.2% by mass or more of the matting agent in the sheath component and 0.2 to 0.5% by mass of the matting agent in the filament, the matting agent is dispersed in the entire fiber by a certain amount or more, and halation. Is suppressed and reduced. With this amount, the strength of the core component does not usually decrease significantly, and the printing durability is also good.
The photosensitive resin used for screen printing may be any photosensitive resin as long as it is for a photosensitive resin for screen gauze, such as a diazo type.

The monofilament for screen gauze of the present invention can be manufactured by melting the resin of the core component and the resin of the sheath component, spinning using a spinneret having a core-sheath structure, and then stretching and relaxing. At this time, a method such as a direct stretching method or a conventional method can be used.
In the production of the monofilament for screen gauze of the present invention, after spinning in the spinning step, sufficient crystallization is performed in the drawing step to fix the fiber structure, and after stretching, the purpose is to reduce the heat shrinkage rate of the drawn yarn. It is preferable to apply a relaxing treatment to alleviate the problem.
As described above, in the stretching step, the monofilament for screen gauze that has been stretched and relaxed is preferable in order to achieve the effect of the present invention.
In the stretching step, it is preferable to perform the main stretching after pre-stretching at a stretching ratio of 1.01 to 1.05 for the purpose of eliminating the deflection. In this stretching, it is preferable to set the temperature of the roll heater to 80 to 88 ° C. for stretching.
In the relaxing treatment in the stretching step, it is preferable to perform heat setting with a plate heater at the same time as the relaxing treatment. The heater temperature at this time is preferably about 120 to 200 ° C.
The relaxation rate in the relaxation process is preferably 1 to 5% from the viewpoint of easily preventing reed scraping and scum generation. The more preferable range of relaxation rates is 2 to 4.5%. When the relaxation rate is less than 1%, the tension between the rollers in the stretching step becomes high, so that the orientation of the amorphous portion becomes high, and reed scraping tends to occur frequently. In addition, pan sink marks occur during weaving, and vertical and horizontal streaks tend to occur in the fabric. When the relaxation rate exceeds 5%, the orientation of the amorphous portion is lowered, so that a high-quality monofilament having a breaking strength and breaking elongation of the present invention is obtained in the above range of 5% modulus and 10% modulus. It's difficult.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the examples described below. The physical characteristics and evaluation of the filament in the examples were as follows.
A. Intrinsic viscosity (IV)
Using a Ubbelohde type viscosity tube, the sample was dissolved in a mixed solvent of phenol: tetrachloroethane = 6: 4, dissolution time 80 ° C. × 1 hour, measured at a measurement temperature of 20 ° C., and intrinsic viscosity IV (dl / g). ) Was obtained.
B. Breaking strength, breaking elongation, 5% modulus, 10% modulus According to JIS L 1013, using AGS-1KNG autograph tensile tester manufactured by Shimadzu Corporation, under the conditions of sample yarn length 20 cm and constant speed tensile speed 20 cm / min. Measure. The value obtained by dividing the maximum value of the load on the load-elongation curve by the fineness is defined as the breaking strength (cN / dtex), the elongation at that time is defined as the breaking elongation (%), and the strength when the elongation is 5% is defined as the breaking strength. The intensity is 5% modulus (cN / dtex), and the intensity when the elongation rate is 10% is 10% modulus (cN / dtex).
C. Hot water shrinkage rate From the length Lo of the thread (filament) measured in a non-tensioned state and the length L of the thread (filament) cooled after being treated in boiling water for 30 minutes without tension, according to the following equation. This is the calculated value.
[Number 1]
Hot water shrinkage rate = (L-Lo) / Lo × 100%
D. Spinning and drawing operability The spinning operability and drawing operability were evaluated as ◯ if the passability of both processes was good, Δ if the process passability was slightly poor, and × if the silk reeling was not possible.
E. Scum evaluation Using the obtained monofilament for screen looms, weave a 300 mesh / inch screen woven fabric at a rotation speed of 300 rpm with a sulzer type loom, and the reeds become dirty and maintain normal weaving. I couldn't do it, so I asked for the weaving length up to the point when the machine stopped.
The evaluation was good when the weaving length was 500 m or more, and x when it was less than 500 m.
F. Reed wear test Pass one fixed monofilament in the direction perpendicular to the reed. The threaded monofilament is tilted 5 ° in the vertical direction with respect to the reed, and the end is fixed with a weight of 1 g / d. The reed is reciprocated up and down 50 mm at a speed of 140 times per minute (1 reciprocation = 1 count). The number of reciprocating motions of the monofilament until it breaks due to the reciprocating motion of the reed is measured. The number of N was 10 and the average was calculated and used as the number of breaks.
G. A printing plate was prepared by applying a diazo resin type photosensitive resin to a photosensitive undyed screen gauze with a film thickness of 10 to 11 μm, appropriately exposing the screen, and washing with water. The presence or absence of halation at this time was observed, and the presence or absence of halation was marked as 〇 for no halation, Δ for the gray zone, and × for halation.
H. Printing durability of screen gauze Using the obtained monofilament for screen gauze, a 300 mesh screen gauze woven fabric was woven to obtain a screen gauze. A screen plate was made using the obtained screen gauze, and the printing pattern at the time of printing 1000 sheets and the damage of the screen gauze were observed. If the print pattern is not distorted or damaged, it is marked with 〇, if it is distorted or slightly damaged, it is marked with x, and if it cannot be determined whether or not it is distorted or damaged, it is marked with △.
I. Dimensional stability Using the obtained monofilament for screen gauze, a woven fabric for screen gauze of 300 mesh was woven to obtain a screen gauze. A screen plate was made using the obtained screen gauze, and the printing pattern at the time of printing 1000 sheets was observed.
J. Comprehensive evaluation Spinning operability / mesh (3 items) are all ○ for 5 items of spinning operability, reed wear test (reed scraping property), and mesh (scum, photosensitivity, printing durability). Those with 30,000 times or more were marked with 〇, those with no x and one or more minor defects were marked with Δ, and those with x even with one item were marked with x.

[Example 1]
Homopolyester terephthalate (IV: 0.85 dl / g) containing 0.3% by mass of solid-phase polymerized titanium oxide was contained in the core, and 0.38% by mass of titanium oxide was contained in polyethylene glycol (PEG: # 400, Copolymerized polyester (IV: 0.65 dl / g, glass transition temperature 66 ° C.) copolymerized with 4.8% by mass / polymer) is placed in the sheath, and the core-sheath ratio (area ratio) is 65:35. An undrawn monofilament was obtained by spinning at a spinning temperature of 299 ° C. and a winding speed of 1110 m / min using a spinning base having an orifice diameter of φ0.37 mm according to a known spinning method. The obtained unstretched monofilament was stretched at a stretching speed of 800 m / min and a roll heater temperature of 84 ° C., and then heat-set at a plate heater temperature of 165 ° C. Obtained a monofilament for use.

[Examples 2 and 3, Comparative Examples 1 and 2]
A 13 dtex monofilament for screen gauze was obtained in the same manner as in Example 1 except that the core-sheath ratio was changed.

[Example 4, Comparative Examples 3 and 4]
A 13 dtex monofilament for screen gauze was obtained in the same manner as in Example 2 except that the intrinsic viscosity of the resin of the core component was changed.

[Comparative Examples 5 and 6]
A 13 dtex monofilament for screen gauze was obtained in the same manner as in Example 2 except that the intrinsic viscosity of the resin of the sheath component was changed.

[Comparative Example 7]
A monofilament for screen gauze was produced in the same manner as in Example 2 except that the titanium oxide concentration in the sheath was set to 0% by mass.

[Comparative Example 8]
A monofilament for screen gauze was produced in the same manner as in Example 2 except that the titanium oxide concentration in the core portion was set to 0% by mass.

[Comparative Examples 9, 10]
A monofilament for screen gauze was produced in the same manner as in Example 2 except that the stretching ratio in the stretching step was changed and adjusted to each elongation.

[Examples 5 and 6]
A monofilament for screen gauze was produced in the same manner as in Example 2 except that the fineness after stretching was changed.

[Examples 7 and 8, Comparative Examples 11 to 13]
A monofilament for screen gauze was produced in the same manner as in Example 2 except that the relaxation rate in the stretching step was changed.

[Comparative Example 14]
A homopolypolyethylene terephthalate (IV: 0.85 dl / g) containing 0.3% by mass of solid-phase polymerized titanium oxide was used in a conventionally known spinning method, using a spinneret having an orifice diameter of φ0.37 mm, and a spinning temperature of 299. Spinning was performed at ° C. and a winding speed of 1110 m / min to obtain an undrawn monofilament. The obtained unstretched monofilament was stretched at a stretching speed of 800 m / min and a roll heater temperature of 84 ° C., and then subjected to a relaxation treatment with a relaxation rate of 4% while heat setting at a plate heater temperature of 165 ° C. for a 13 dtex screen gauze. A monofilament was obtained.

[Comparative Example 15]
A copolymerized polyester (IV: 0.65 dl / g) containing 0.38% by mass of titanium oxide and copolymerized with polyethylene glycol (PEG: # 400, 4.8% by mass / polymer) was prepared according to a conventionally known spinning method. Using a spinneret having an orifice diameter of φ0.37 mm, spinning was performed at a spinning temperature of 299 ° C. and a winding speed of 1110 m / min to obtain an undrawn monofilament. The obtained unstretched monofilament was heat-set at a stretching speed of 800 m / min, a roll heater temperature of 84 ° C., and a plate heater of 165 ° C., and subjected to a relaxation treatment with a relaxation rate of 4% to obtain a monofilament for screen gauze of 13 dtex. ..

Table 1 shows the production conditions, yarn characteristics, and evaluation results of the monofilaments of Examples 1 to 8 and Comparative Examples 1 to 15.

The monofilament for screen gauze made of high-viscosity polyethylene terephthalate and polyethylene glycol-containing copolymer polyethylene terephthalate obtained from Examples 1 to 8 was a monofilament having high strength and high modulus and good yarn quality with little reed scraping. .. Further, the woven fabric for screen gauze obtained from these monofilaments for screen gauze had no scum and was of good quality. Further, the screen gauze had good dimensional stability, no scum, good adhesiveness to the photosensitive resin, no halation, and high quality in printing durability. In Example 8, pan sink marks were seen from the monofilament in the innermost layer of the pan roll, and some streaks were seen in the fabric, but in the layers other than the innermost layer, the same good monofilament as described above was obtained. In the monofilaments of Examples 1 to 7, no pan sink marks were observed in both the outer layer and the inner layer, and the quality was particularly high. In addition, among them, those of Examples 2 to 4, 6 and 7 had good fiber physical characteristics, did not generate scum, halation, and thread scraping, and obtained a screen gauze having particularly excellent printing durability.
The monofilament for screen gauze obtained from Comparative Example 1 in which the ratio of the cores was small had no knotting threads and scum, and there was no reed scraping due to reed wear, but the screen gauze was inferior in printing durability.
The monofilament for screen gauze obtained from Comparative Example 2 in which the ratio of the sheath is small is inferior in quality due to reed scraping and scum generation during weaving, and scraping from the screen gauze during screen printing. It became a screen gauze.
The monofilament for screen gauze obtained from Comparative Example 3 in which the core portion was made of low-viscosity polyester had a low breaking strength and modulus of the monofilament, resulting in a screen gauze having poor printing durability.
In the monofilament for screen gauze obtained from Comparative Example 4 in which the core portion had a high viscosity, knots were generated in the core portion due to unmelted material, scum was generated during weaving, and the obtained screen gauze was printed. It became inferior in durability.
The monofilament for screen gauze obtained from Comparative Example 5 in which the sheath portion has a low viscosity has a large difference in viscosity between the core side and the sheath side, has very poor spinning operability, and has a poor shape of the fiber cross section. Met. Reed wear is likely to occur during weaving, and the obtained screen gauze has poor printing durability and poor quality.
The monofilament for screen gauze obtained from Comparative Example 6 having a high viscosity of the sheath portion has a poor quality screen gauze, such as reed scraping during weaving and knots due to unmelted resin on the sheath side. became. This is because the molecular orientation of the sheath resin becomes too high due to the increased sheath viscosity, which causes reed scraping and knots due to the unmelted material of the resin on the sheath side, resulting in poor quality. It seems that it became a screen gauze.
The monofilament for screen screen obtained from Comparative Example 7 in which the titanium oxide concentration in the sheath was 0% by mass was obtained as a monofilament having high reed wear resistance during weaving and no scum generation, but halation during screen printing. It became a low-quality screen gauze.
The monofilament for screen gauze obtained from Comparative Example 8 in which the titanium oxide concentration of the core resin was 0% by mass was such that halation of the photosensitive resin occurred during screen printing, and precise printing was not possible.
In the monofilament for screen gauze obtained from Comparative Example 9 having a breaking elongation of 15%, reed scraping occurred frequently and scum occurred during weaving. The obtained screen gauze had low printing durability and was of low quality. In the obtained monofilament, the molecular chains were highly oriented in the fiber axis direction, so that it is considered that reed scraping occurred frequently and scum occurred.
The monofilament for screen gauze obtained from Comparative Example 10 having a breaking elongation of 45%, a breaking strength of 5.8 cN / dtex, and a modulus of 10% of 4.8% has sufficient dimensional stability. However, the print durability was inferior and the quality was poor.
The monofilament for screen gauze obtained from Comparative Example 11 having a relaxation rate of 10% had lower 5% modulus and 10% modulus. The obtained screen gauze was not of high quality capable of high-precision precision printing, and had poor printing durability.
The monofilament for screen gauze obtained from Comparative Example 12 having a relaxation rate of 7% had a low 5% modulus. The obtained screen gauze was not of high quality capable of high-precision precision printing, and had poor printing durability.
The monofilament for screen gauze obtained from Comparative Example 13 having a relaxation rate of -7% (7% stretch) had a high 5% modulus. Reeds were worn during weaving, scum was observed, a large amount of pan sink marks were generated, and streaks were generated on the fabric. The obtained screen gauze had low quality and was inferior in printing durability. It is considered that this is because the orientation of the sheath part progressed in the relaxing process, and reed wear and scum generation occurred.
The polyethylene terephthalate monofilament obtained in Comparative Example 14 had scum and reed scraping during weaving, and the obtained screen gauze had poor quality due to misalignment and was also inferior in printing durability.
The polyethylene glycol copolymer polyethylene terephthalate monofilament obtained in Comparative Example 15 had insufficient strength and modulus, and the obtained screen gauze had poor dimensional stability, difficulty in high-precision printing, and inferior in printing durability. It was a thing.

As described above, the monofilaments for screen gauze obtained from Examples 1 to 8 were of high strength and high quality without reed scraping, scum, knotting, and pan sink marks during weaving. The obtained screen gauze has excellent adhesiveness to the photosensitive resin, does not cause thread breakage, scum, or misalignment when the screen gauze is stretched, does not cause halation, and has good dimensional stability, so high-precision printing is possible. It was a high-quality product with excellent printing durability.

Claims (4)

A monofilament for screen gauze, wherein the core component is polyester and the sheath component is a copolymerized polyester core-sheath monofilament, which satisfies (1) to (8).
(1) The resin of the core component has an intrinsic viscosity (IV) of 0.7 to 1.0 dl / g. Homo polyethylene terephthalate (2) The resin of the sheath component has an intrinsic viscosity (IV) of 0.55 to 0. Modified polyethylene terephthalate copolymerized with polyethylene glycol having a viscosity of .68 dl / g (3) Core-sheath ratio (area ratio) is 65:35 to 90:10.
(4) Breaking strength is 6.2 to 7.5 cN / dtex
(5) Elongation at break is 20-28%
(6) 5% modulus is 3 to 4.5 cN / dtex
(7) 10% modulus is 5-7cN / dtex
(8) The concentration of the matting agent of the core component is 0.05 to 0.5% by mass, and the concentration of the matting agent of the sheath component is 0.2 to 0.5% by mass. The monofilament for screen gauze according to claim 1, which is obtained by stretching and relaxing treatment. The monofilament for screen gauze according to claim 1 or 2, wherein the monofilament does not break when the number of times of raising and lowering is 30,000 or more in the reed wear test under the following conditions.
Condition: Pass one fixed monofilament in the direction perpendicular to the reed. The threaded monofilament is tilted 5 ° in the vertical direction with respect to the reed, and the end is fixed with a weight of 1 g / d. Move the reed up and down (1 round trip = 1 count) on the monofilament. The average number of times the monofilament is cut at this time is counted. Modification of homopolyethylene terephthalate having an intrinsic viscosity (IV) of 0.7 to 1.0 dl / g as a core component and polyethylene glycol having an intrinsic viscosity (IV) of 0.55 to 0.68 dl / g. Claims 1 to 3 which are methods for producing a core sheath monofilament for screen gauze, which uses polyethylene terephthalate as a sheath component and is stretched after being spun from a spinneret, and is subjected to a relaxation treatment of 1 to 5% in the stretching step. The method for manufacturing a core sheath monofilament for screen gauze according to any one of the above items.