JPH1178275A - Screen gauze - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide screen gauze excellent not only in dimensional stability, mechanical capacity and fibrile resistance but also in printing characteristics. SOLUTION: Screen gauze is formed of a core-sheath type composite fiber wherein a core component is composed of molten liquid crystal polyester (A- polymer) and a sheath component consists of a bendable thermoplastic polymer (B-polymer) and molten liquid crystal polyester (C-polymer) and the compounding ratio of the C-polymer in the sheath component is 0.15-0.45. The core-sheath type composite fiber has a color specification value represented by formula (1); 18<=b*<=35, formula (2); 0.5<=a*<=10 and formula (3); 55<=L:<=80 (wherein b * is 200 [(Y/Y0 )<1/3> -(Z/Z0 )<1/3> ]; a * is 500 [(X/X0 )<1/3> -(Y/Y0 )<1/3> ]; L * is 116(Y/Y0 )<1/3> -16 and X, Y and Z is tristimulus values of a perfect diffusion surface).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a screen gauze.

[0002]

2. Description of the Related Art In order to realize high-density and high-precision printing with a screen gauze, it is required that high tension gauze can be applied, dimensional change is small, and elastic recovery is large. Screen gauze using fibers made of a flexible polymer such as nylon or polyester is widely used, but such screen gauze has low strength and elastic modulus and does not always have good dimensional stability. For this reason, in the field of high-performance printing such as printing on a printed wiring board, a screen gauze made of stainless fine wire has been used. However, stainless fine wire has problems such as low handleability. To solve the above problems, a screen gauze using a molten liquid crystalline polyester fiber is disclosed in Japanese Patent Laid-Open No. 2-806.
No. 40, JP-A-3-220340 and the like.

[0003]

The screen gauze made of only the molten liquid crystalline polyester fiber has no problem in strength and elastic modulus, however, since it is a rigid polymer, its surface is easily fibrillated, and fibrils generated in the weaving process are produced. However, there is a problem that ink permeability is hindered and high-precision printing is hindered. Also, screen gauze using sea-island fiber containing molten liquid crystalline polyester as an island component and polyethylene terephthalate as a sea component, or core-sheath composite fiber containing molten liquid crystalline polyester as a core component and another flexible polymer as a sheath component is also available. Although it has been proposed, the flexible polymer constituting the sheath component and the sea component is not stretched, so that it is very brittle, not only the mechanical strength becomes insufficient, but also the problem that peeling or falling off of the sheath is likely to occur. there were. When the ratio of the island component or the core component is increased to obtain sufficient mechanical performance, the core component is exposed and the abrasion resistance is reduced, and production on an operation scale is extremely difficult.

In order to solve the above problems, the present inventors have proposed that a core component is a molten liquid crystalline polyester (A polymer),
JP-A-5-230715 and JP-A-5-230715 disclose a screen gauze using a core-sheath composite fiber whose sheath component is composed of a blend of a flexible thermoplastic polymer (B polymer) and a molten liquid crystalline polyester (C polymer). 8-26
No. 0249 proposes this. Such screen gauze is not only excellent in dimensional stability and mechanical performance,
It was excellent in fibril resistance and had performance higher than that of a screen gauze made of fine stainless steel wire.
An object of the present invention is to provide a screen gauter having further excellent printing characteristics.

[0005]

According to the present invention, there is provided: 1) a liquid crystal polyester having a core component of a molten liquid crystalline polyester (A polymer).
The sheath component is composed of a flexible thermoplastic polymer (B polymer) and a molten liquid crystalline polyester (C polymer), and the compounding ratio of the C polymer is 0.15 to 0.1.
45, and the following (1) to
A screen gauze characterized by using a core-sheath composite fiber having a color value shown in (3), 18 ≦ b * ≦ 35 (1) 0.5 ≦ a * ≦ 10 (2) 55 ≦ L * ≦ 80 (3) (However, b * = 200 [(Y / Y ₀ ) ^{1 _{/ 3 - (Z / Z 0}} )
^1/3 ], a * = 500 [(X / X ₀ ) ^1/3 − (Y / Y ₀ ) ^1/3 ], L * = 116 (Y / Y ₀ ) ^1/3 -16, and X , Y, Z are the tristimulus values of the perfect diffusion surface. 2) The screen gauze according to 1), wherein the strength of the core-sheath conjugate fiber constituting the screen gauze is 10 g / d or more; 3) The elastic modulus of the core-sheath conjugate fiber constituting the screen gauze Is 400 g / d or more; 4) The screen gauze according to 1) or 2), 4) the content of the coloring agent contained in the core-sheath composite fibers constituting the screen gauze is 0.1% by weight or less. 5) The screen gauze according to any one of 1) to 3), 5) wherein the flexible thermoplastic polymer constituting the core-sheath composite fiber is polyphenylene sulfide. The screen gauze according to any one of 4) to 6), wherein the diameter of the core-sheath composite fiber is 45 μm or less 1).
7) The screen gauze according to any one of 5) to 7), wherein the surface of the core-sheath composite fiber constituting the screen gauze is formed with gentle undulations 1).
8) The screen gauze according to any one of 1) to 7), wherein the screen gauze is a mesh fabric using a core-sheath composite monofilament. 9) The screen gauze is configured. When the tear strength of the mesh fabric to be formed is X (gf) and the yarn diameter of the yarns arranged along the tear direction among the yarns constituting the mesh fabric is Y (μm), the value of X / Y ² is 0. The screen gauze according to 8), which has an opening area of 35% or more, and which has a tear strength of 200 gf or more.
11) The density is 200 mesh or more 1) to 10)
12) The screen gauze according to 1), wherein the compounding ratio of the C polymer is 0.25 to 0.4.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The term "molten liquid crystalline property (anisotropic)" as used in the present invention means that it exhibits optical liquid crystalline property (anisotropic) in a molten phase. For example, it can be recognized by placing the sample on a hot stage, heating and heating the sample in a nitrogen atmosphere, and observing the transmitted light of the sample. The aromatic polyester used in the present invention is composed of a repeating structural unit such as an aromatic diol, an aromatic dicarboxylic acid, or an aromatic hydroxycarboxylic acid, and is composed of a combination of repeating structural units represented by the following chemical formulas 1, 2, and 3. Are preferred.

[0007]

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[0008]

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[0009]

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Particularly preferably, the compounds of formulas (11) and (1)
It is a polymer comprising a combination of the repeating structural units shown in 2). Among them, a polymer in which the portion composed of the repeating structural units of (A) and (B) in (11) is at least 65% by weight is preferable, and an aromatic polyester whose component (B) is from 4 to 45% by weight is particularly preferable. .

The melting point (MP) of the molten liquid crystalline polyester is preferably from 260 to 360 ° C., more preferably from 270 to 360 ° C.
350 ° C. The melting point referred to here is a differential scanning calorimetry (DSC: manufactured by Mettler, TA3000, for example).
Is the peak temperature of the main endothermic peak observed in (JIS)
K7121). Specifically, after taking 10 to 20 mg of a sample in a DSC device and sealing the sample in an aluminum pan, 100 cc / min of nitrogen was flowed as a carrier gas at 20 ° C.
The endothermic peak is measured when the temperature is raised at a rate of / minute. If a clear endothermic peak does not appear in the first run depending on the type of the polymer, the temperature is raised to a temperature 50 ° C. higher than the expected flow temperature at a rate of 50 ° C./min.
After completely melting for one minute, it is preferable to cool to 50 ° C. at a rate of 80 ° C./min, and then measure the endothermic peak at a rate of temperature rise of 20 ° C./min.

The B polymer used in the present invention is not particularly limited as long as it is a flexible thermoplastic polymer.
Examples include polyolefin, polyamide, polyester, polycarbonate, polyphenylene sulfide (PPS), polyetheretherketone, and fluororesin. In particular, it is preferable to use PPS or polyethylene naphthalate as the B polymer. In particular, when PPS, particularly linear PPS, is used, the spinning processability is improved, and chemical resistance, mechanical strength, abrasion resistance, etc. In this respect, a remarkable effect can be obtained. Incidentally, the flexible polymer in the present invention,
It refers to a polymer having no aromatic ring on the main chain and a polymer having an aromatic ring on the main chain and having four or more atoms on the main chain between the aromatic rings.

As the C polymer, the same molten liquid crystalline polyester as the A polymer can be used, and the A polymer and the C polymer may be the same or different.
The melting point of the C polymer is preferably not more than [the melting point MP of the B polymer + 80 ° C.] and not less than [the melting point MP of the B polymer−10 ° C.] from the viewpoints of spinnability and fiber coloring property.

The A and C polymers used in the present invention include:
As long as the effects of the present invention are not impaired, a thermoplastic polymer such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, polyetheretherketone, or a fluororesin may be added. In addition, a polymer other than the flexible thermoplastic polymer may be contained as long as the effect of the present invention is not impaired, and a plurality of types of flexible thermoplastic polymers may be used. In addition, A, B and C polymers include inorganic substances such as titanium oxide, kaolin, silica and barium oxide, carbon black, coloring agents such as dyes and pigments, antioxidants, as long as the effects of the present invention are not impaired. Various additives such as an ultraviolet absorber and a light stabilizer may be blended.

According to the present invention, not only the flexible thermoplastic polymer (B polymer) but also the flexible thermoplastic polymer (B
(Polymer) and a molten liquid crystalline polyester (C polymer), thereby enhancing the strength of the sheath component and remarkably enhancing the adhesiveness between the sheath component and the core component. The blend constituting the sheath component can be obtained by chip blending the B polymer and the C polymer, or by mixing a melt of both components with a static mixer or the like.
In the present invention, since the sheath component is constituted by using a larger amount of the soft B polymer than the C polymer, the sheath component forms a sea-island structure in which the C polymer is an island component and the B polymer is a sea component. (Figure 2). In the figure, A is A
A polymer, B represents a B polymer, and C represents a C polymer. In this case, the rigid C polymer having excellent mechanical performance constitutes an island component and has an excellent reinforcing effect.
It is considered that the wear resistance is remarkably improved because the B polymer having excellent wear resistance forms a sea component and substantially covers the periphery of the C polymer. The sea-island structure according to the present invention refers to a state in which tens to tens of thousands of islands are present in a sea component serving as a matrix in a fiber cross section. Generally, the number of islands can be adjusted by changing the mixing ratio of B polymer and C polymer and the melt viscosity. Fiber strength,
From the viewpoint of fibril resistance and the like, it is preferable that the island component is fine, and that the diameter is preferably about 0.01 to 0.5 μm.

In order to increase the strength of the B polymer constituting the sheath component, it is necessary to stretch the fiber sufficiently to orient the B polymer, but the molten liquid crystalline polyester constituting the core component was spun without being stretched. Alone has excellent mechanical performance, and the orientation is remarkably advanced in the state of the spun yarn. Therefore, even if an attempt is made to further stretch the spun yarn in order to increase the strength of the sheath component, it is not possible to stretch substantially further because the A polymer constituting the core component is highly oriented. As a result, the sheath component of the obtained conjugate fiber has low strength and is brittle, the core component and the sheath component are easily separated, and the workability and abrasion resistance are insufficient, and further, the core-sheath component is separated. Fibrils occur,
High-precision printing in which the ink permeability is impaired is impeded.

However, in the present invention, since the molten liquid crystalline polyester is blended with the sheath component, the affinity for the core component made of a similar polymer is increased, so that the core-sheath separation hardly occurs and the sheath component is hardly separated. Is highly oriented in the state of a spun yarn, the strength of the sheath component is improved, and the abrasion resistance and the like are significantly improved. In particular, even when the opening area of the screen gauze is reduced, excellent performance such as dimensional stability and wear resistance is exhibited. Compounding ratio of C polymer in sheath component (C / B
+ C) is 0.15 to 0.45, preferably 0.25 to
0.4 (weight ratio). If the compounding ratio of the C polymer is too high, the abrasion resistance becomes insufficient, and the workability of weaving or the like decreases because the fibers become rigid. Conversely, if the blending ratio of the C polymer is too low, the strength of the sheath component becomes insufficient, the core-sheath peeling is likely to occur, and the processability such as weaving property is reduced. Further, it becomes difficult to obtain a desired color specification value.

In the present invention, the core-sheath type composite fiber is targeted, and the form of the core-sheath type includes an eccentric core-sheath type and a multi-core sheath type. The core component ratio in the composite fiber is preferably 0.25 to 0.80, particularly preferably 0.3 to 0.7. In addition, the core component ratio in the present invention indicates a cross-sectional area ratio (A) / (A + B + C) of the conjugate fiber. The cross-sectional area ratio can be determined from a micrograph of the cross-section of the fiber, but can also be determined from the volume ratio of the discharge amount of the core component and the sheath component during production.

A major feature of the present invention is that a core-sheath composite fiber having a specific color specification value is used. By setting to a specific color value, halation hardly occurs at the time of exposure of the emulsion, the boundary between the masking portion and the non-masking portion becomes clear, and a precise and dense pattern can be formed. The colorimetric values b *, a *, and L * are those recommended by the CIE in 1976, and are defined by the following equation when X, Y, and Z are tristimulus values of a perfect diffusion surface. is there. 18 ≦ b * ≦ 35 (1) 0.5 ≦ a * ≦ 10 (2) 55 ≦ L * ≦ 80 ... (3) (wherein, b * = 200 ^{_{[(Y / Y 0) 1/3 -}} (Z / Z 0)
^1/3 ], a * = 500 [(X / X ₀ ) ^1/3 − (Y / Y ₀ ) ^1/3 ], L * = 116 (Y / Y ₀ ) ^1/3 -16, and X , Y, Z are the tristimulus values of the perfect diffusion surface. In general, b * indicates yellow, a * indicates red, and L * indicates white. The larger the numerical value, the more yellow, red and white. These color values can be easily measured by a color analyzer (for example, Model C-200S manufactured by Hitachi, Ltd.).

By using the colored conjugate fiber having such a color specification value, the influence of halation is reduced, the boundary between the masking portion and the non-masking portion becomes clear, and a precise and dense pattern can be formed. Therefore,
Clear fine line pattern printing, which cannot be obtained with a screen gauze made of stainless fine lines, becomes possible. In particular, the b * value has a large effect on printing characteristics, and is more preferably 20 to 35, particularly 25 to 33.

When b * is too small, halation occurs and the sharpness of the ridgeline becomes insufficient, and when b * is too large, not only yellowish but also blackishness increases, and light hardly passes through the back side of the yarn. There is a possibility that the exposure of the emulsion on the back side may be hindered. And a
If * is too small, even if b * is appropriate, only the yellowish color will become strong and the effect of preventing halation will be reduced. Conversely, if too large, redness will be too strong and the effect of preventing halation will be reduced. On the other hand, if L * is too small, grayness increases and the halation prevention effect becomes small, while if L * is too large, the color becomes close to white and the halation prevention effect similarly becomes small. a * value is 1.0 or more and 5.5 or less, L
* The value is more preferably 60 or more and 78 or less.

The method for obtaining the fiber having such a color value is not particularly limited, and examples thereof include a method in which a B-type polymer and / or a C-type polymer contain a yellowish colorant (eg, a pigment or a dye). As a method of mixing the colorant, a predetermined amount may be directly added to the B polymer and / or the C polymer, or a high concentration master chip may be diluted by a blending method at the time of fiber production. As the coloring agent, carbon black, a pigment (including titanium oxide), and a dye having heat resistance can be used, and those having a particle size of 0.01 to 2 μm are preferably used.

However, when a coloring agent is added, there is a problem that the mechanical performance of the fiber is deteriorated and the core / sheath component is easily peeled off. Therefore, the amount of the coloring agent is preferably 0.1% by weight or less, particularly 0.01% by weight or less based on the total weight of the fibers. More preferably, the coloring agent is added without substantially adding the coloring agent. It is preferred to color the fibers in a manner that does not depend on the fiber. When fiber diameter is small, especially fiber diameter 33μm
In the following cases, the effect of blending the coloring agent becomes large. Usually, when a molten liquid crystalline polyester fiber is subjected to a heat treatment in an active atmosphere, a fiber having a desired color specification value is obtained. However, when the sheath component is composed of a blend of a B polymer and a C polymer, a usual method is used. In such a case, such a composite fiber cannot be obtained. Although the reason for this is not clear, when the blending ratio of the B polymer constituting the sheath component is high, a sea-island structure is formed in which the C polymer is an island component and the B polymer is a sea component. This is presumed to be because the material is substantially covered by a certain B polymer, and thus does not color to a desired color specification value even if heat treatment is performed in an active atmosphere. If the compounding ratio of the C polymer is increased, the fibers are more likely to be colored, but the weaving property and the abrasion resistance are reduced.

However, even if a resin such as PPS, which originally has a white color, is used as the B polymer,
For example, by adopting the following specific conditions, a colored fiber having the above color specification value can be obtained. As a preferable production method, the weight ratio C / (B + C) of the C polymer to the total weight of the B polymer and the C polymer is 0.15 to 0.15.
A method of spinning to 0.45 and satisfying the following conditions, and then performing a heat treatment in an active atmosphere.

MVb ≧ MVc Spinning temperature ≧ MPc + 30 ° C. γ (γ = 4Q / πr ³ ) ≧ 20,000 In addition, MVb and MVc are the melt viscosities (poise) of the B polymer and the C polymer measured by the method described in Examples, respectively. ), MPc is the melting point (° C.) of the C polymer, γ is the shear rate during spinning (sec ⁻¹ ), and Q is the amount of polymer discharged per single hole (cm ³ ) when spinning the core-sheath composite fiber. / S
ec) and r indicate the radius (cm) of the nozzle hole in the shear plane direction.

The reason why a conjugate fiber having a desired color specification value can be obtained by adopting such a method is not clear, but the C polymer forms a fine island component and the C polymer has a smaller island component than the B polymer. By applying a high shearing force in a state where the viscosity is sufficiently reduced, island components composed of the C polymer are unevenly distributed near the fiber surface, and then heat treatment in an active atmosphere causes various C polymers near the fiber surface. It is presumed that it is colored by various side reactions and exhibits a specific color specification value. In particular, when a linear PPS is used as the B polymer, a composite fiber having excellent mechanical strength and a desired color value can be obtained efficiently by adjusting the oxygen concentration, the processing temperature, and the processing time. .

From the viewpoint of coloring efficiency, γ is more preferably 30,000 or more, particularly preferably 40,000 or more. The reason for this is not clear, but by increasing the shear rate the C
It is considered that the island component composed of the polymer is more likely to be unevenly distributed near the fiber. From the viewpoint of spinnability and coloring properties, it is preferable to increase the shear rate as the fiber diameter increases.
Further, from the viewpoint of spinning processability, it is preferably at most 80,000. Further, when the above method is employed, the spinning temperature needs to be not lower than MPc + 30 ° C. Although the reason for this is not clear, it is considered that if the spinning temperature is too low, the viscosity of the C polymer does not sufficiently decrease, so that it is impossible for the island component composed of the C polymer to be unevenly distributed near the fiber surface. However, if the spinning temperature is increased, the polymer may be decomposed in some cases. Therefore, the temperature is preferably set to MPc + 60 ° C. or lower.

The spinning speed is preferably 650 m / min or more, particularly 900 m / min or more, from the viewpoint of improving the coloring efficiency and fiber performance, and is preferably 3000 m / min or less from the viewpoint of spinning stability. MVb is (MVc + 1100) poise from the viewpoint that spinnability and a fiber having a small yarn diameter are easily obtained.
It is preferred that: It is preferably MVc or more from the viewpoint of coloring property and the like, and MVc + 350 or more, particularly MVc
More preferably, it is +400 or more. MVc is 600 poise in terms of spinnability, coloring efficiency, abrasion resistance of fiber, etc.
Hereafter, it is particularly preferably 500 poise or less, and more preferably 380 poise or more from the viewpoint of fiber performance.

The heat treatment does not need to be performed in all steps in an active atmosphere, and at least a part of the steps may be performed in an active atmosphere. At this time, either a relaxation heat treatment or a tension heat treatment may be used. From the viewpoint of the coloring effect and the fiber performance, it is preferable to employ a temperature condition of (MPb-80 ° C) to (MPb ° C). It is preferred to do so. Here, MPb represents the melting point of the B polymer. The heat treatment atmosphere is preferably a low-humidity gas having a dew point of −40 ° C. or less, and it is preferable to perform the heat treatment in a temperature pattern in which the temperature is sequentially increased from the melting point of the core component of −40 ° C. or less to the melting point of the sheath component polymer or less. Processing time can range from a few minutes to 5
Perform for 0 to 60 hours.

Heat is supplied in the heat treatment by a method using a medium such as a gas, a method using radiation from a heating plate or an infrared heater, a method using a medium in contact with a heat roller, a heat plate, or the like, an internal method using high frequency or the like. A heating method or the like can be used. The shape of the heat treatment may be a scallop shape, a tow shape (for example, placed on a metal net or the like), or a continuous treatment between rollers. In the case of performing the tension heat treatment, at a temperature lower than the melting point of the core component −80 ° C., the cutting strength of 1%.
The treatment is preferably performed under a tension of 10% to 10%, and this treatment further improves various performances, particularly elastic modulus. Although heat treatment may be performed after forming the fabric, heat treatment is preferably performed before forming the fabric from the viewpoint of processability.

To enhance the coloring effect and the like, an oil agent is added to the spun yarn at 0.01% by weight or more, especially 0.0% by weight based on the weight of the fiber.
Heat treatment is preferably performed after 5% by weight or more is attached. The oil agent on the surface of the fiber functions to promote various side reactions, and promotes coloring which is convenient for the present invention. In addition, the coloring effect is remarkably improved by applying the oil agent. Therefore, even when the fiber is spun by the above-described specific method and heat-treated in an inert atmosphere (for example, a nitrogen atmosphere), the present invention A conjugate fiber having a color specification value defined in (1) is obtained. From the viewpoint of fiber performance, the amount of the oil agent attached is preferably 3% by weight or less, particularly preferably 1% by weight or less.

As the oil agent, those which evaporate during the heat treatment are preferred from the viewpoint of the coloring effect, and the emulsion oil agents are preferred from the viewpoint of easy application to the fiber. An oil agent that imparts smoothness and antistatic properties to the fiber is preferably used. Specifically, an oil agent containing a mineral oil, an alkylene oxide copolymer, and an aliphatic ester as main components is suitably used. Among them, from the above points, the general formula (1)
It is preferable to use the oil agent described in 3) and / or the general formula (14) shown in Chemical formula 5, and a more remarkable effect can be obtained by using these in combination.

[0033]

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[0034]

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In the general formulas (13) and (14), R is a hydrocarbon group having 3 to 30 carbon atoms, n is an integer of 1 to 30; m is an integer of 1 to 30; X represents Na or K. In particular, R is a straight-chain hydrocarbon group having 8 to 15 carbon atoms, n is an integer of 8 to 15; m is an integer of 1 to 5; Is more preferred. Among them, the oil agents represented by the general formula (15) shown in Chemical formula 6 and the general formula (16) shown in Chemical formula 7 can be particularly preferably used. The mixing ratio (weight ratio) of the oil agent described in the general formula (13) and the oil agent described in the general formula (14) is preferably 30:70 to 70:30.

[0036]

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[0037]

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The fiber can be colored to a desired color value by satisfying the above conditions and performing the heat treatment. However, the coloration effect is obtained by the heat treatment and the mechanical performance of the fiber is remarkably improved. Can be increased. The heat treatment for the purpose of coloring and the heat treatment for the purpose of improving the mechanical performance may be performed in the same process, but may be performed in different processes. For example, after heat treatment for improving mechanical performance is performed, heat treatment for coloring may be performed in the air or the like. If the heat treatment conditions corresponding to each purpose are different, after performing a heat treatment to achieve one of the purposes, and then continue to perform heat treatment only for the shortage to achieve the other purpose, It is preferable to achieve the purpose. The heat treatment for the purpose of improving the mechanical performance of the fiber can be performed in an atmosphere of an inert gas such as nitrogen, an atmosphere of an active gas containing oxygen such as air, or under reduced pressure.

When a conjugate fiber is produced by a method in which a colorant is not substantially blended, excellent performance is obtained because the mechanical performance of the fiber is not impaired. Specifically, fiber strength 10g
/ D or more, elastic modulus 400 g / d or more, especially strength 12 g / d
Above, the elastic modulus is 450 g / d or more, and the strength is 16 g / d.
As described above, a conjugate fiber having an elastic modulus of 500 g / d or more is obtained.
When using fibers with high strength and elastic modulus, dimensional stability,
A screen gauze excellent in various performances such as durability and printing characteristics can be obtained.

In the present invention, it is more preferable to form irregularities on the fiber surface. By forming the uneven portions, the adhesiveness to a photosensitive resin or the like is improved, and excellent effects such as abrasion resistance can be obtained. There is no particular limitation on the method of providing the uneven portion, and examples thereof include a method of spinning using a nozzle having a hole with an irregular cross section, a method of forming a fine shape by partial drawing, a method of containing a large number of inorganic fine particles in a polymer, and a fiber. Conventionally known methods such as a method of etching by chemical treatment after the formation and a method of etching by plasma treatment can be adopted.

By employing such a method, a conjugate fiber having a large number of extremely fine irregularities can be obtained. However, since abrasion of the irregularities hardly occurs due to abrasion and a more remarkable effect can be obtained, the surface is gentle. It is preferable to use fibers having undulations. Various effects can be obtained by forming gentle undulations on the fiber surface. For example, heat treatment at higher temperatures becomes possible due to less sticking during heat treatment, and furthermore, frictional resistance is small and processability (weaving property etc.) is reduced. ) Is good.

The particularly excellent effect is that the adhesion to a photosensitive emulsion (hereinafter, simply referred to as an emulsion) can be enhanced and the durability of a printing plate can be improved. The emulsion can be formed in a pattern so that the edge of the emulsion is sharp in a plan view and nearly vertical in a sectional view. As a result, printing properties can be remarkably improved, such as good ink bleeding property, making and using a printing plate having an emulsion layer formed in a narrow width, that is, enabling pattern printing at a fine pitch. In particular, there is an excellent effect in a field where precision and sharpness are required.

According to the present invention, a gentle undulation is formed on the fiber surface, and the scanning electron micrograph of FIG. 3 shows a gently undulated shape on the fiber surface. Unlike those in which fine undulations are formed in this way, unlike those in which fine irregularities are formed by fine particles and the like, guide abrasion and the cutting of the yarn itself are less likely to occur, and weaving of high-density screen gauze becomes easier. At the same time, a remarkable effect can be obtained because the clogging and the ink removal property are improved. Further, as compared with the case where a large number of fine irregularities are formed, the irregularities are less likely to disappear due to abrasion, so that a more excellent effect can be obtained. The method of forming the uneven portion is not particularly limited, but, for example, the following method is employed.

0.15 ≦ C / (B + C) ≦ 0.45 MVb ≧ MVc + 350 γ (γ = 4Q / πr ³ ) ≧ 20000 C / (B + C) indicates the weight ratio of the C polymer.
Vb, MVc, γ, Q, and r have the same meanings as those used in the above-mentioned formulas representing spinning conditions. Although the mechanism by which the above-described method forms gentle undulations is not clear, the rigid C polymer forms streak-like protrusions because the C polymer becomes a very fine island component and is distributed on the fiber surface in large amounts. It is thought that.

In order to form gentle undulations, it is preferable that the viscosities of the B polymer and the C polymer have a specific relationship. The viscosity MVb of B polymer is (MVc + 350) pois
When it is less than e, a clear undulating structure is difficult to be formed,
Conversely, the viscosity MVb of the B polymer is (MVc + 1100) po
If it exceeds ise, a phenomenon similar to melt fracture occurs under the nozzle, which not only reduces spinnability but also makes it difficult to obtain fibers having a small yarn diameter. It is preferable that MVb ≧ MVc + 400 from the viewpoint of the formation of the relief structure. When a linear PPS is used as the B polymer, the spinning property is excellent and the mechanical performance is also excellent, and a smooth undulation is easily formed.

If the ratio deviates from 0.15 ≦ C / (B + C) ≦ 0.45, the reason why smooth undulations are not formed is not obvious. However, when the blending ratio of the C polymer is small, the number of island components composed of the C polymer is small. It is considered that undulations caused by the C polymer are hardly formed, and conversely, if the compounding ratio of the C polymer is too large, island components made of the C polymer are hardly formed.

A preferred form of the undulating fiber of the present invention is shown in FIG. As shown in FIG. 4, the profile of the outer periphery of the fiber side surface of the fiber side surface photograph taken at a magnification of 1000 with a scanning electron microscope was drawn (in the figure,
1 is a fiber, 2 is a fiber side outer peripheral outline), a maximum point existing between fiber lengths 3D (D: average fiber diameter) is L, a minimum point is S, and a perpendicular line from the center line C to L Is LL and the length of the perpendicular from the center line C to S is LS, the difference (LL-LS) between adjacent LL and LS is 0.00.
The number (NM) of combinations of adjacent L and S that is 5D or more is obtained as the sum of both side surfaces, and it is preferable that the average value of NM at three or more measurement positions be 5 to 100, particularly The average value is preferably 10 to 50. From the viewpoint of fiber strength, etc., (LL-LS) is 0.05
D or less, particularly preferably 0.03D or less. still,
The center line C according to the present invention is a line segment (a, b) in the fiber diameter direction which is divided into fiber lengths 3D, and these line segments a and b
Is a straight line connecting the centers of

The core-sheath conjugate fiber used in the present invention can be spun by a known method, for example, using a nozzle shown in FIG. In the figure, A indicates A polymer, B indicates B polymer, and C indicates C polymer. The cross-sectional shape of the obtained fiber is not particularly limited.
Shapes as shown in (a) to (g) and FIG. 2 are preferred examples. In FIG. 1, A is A polymer, B is
Represents a B polymer, and C represents a C polymer. A polymer constitutes the core component, and the mixture of B polymer and C polymer constitutes the sheath component. It is considered that the sheath component has a sea-island structure composed of a sea component and an island component. FIG.
Fig. 3 shows a state in which it is considered that the B polymer constitutes the sea component and the C polymer constitutes the island component. By using the core-sheath type composite fiber as described above, bleeding or blurring of a printed image does not occur, problems such as poor leveling are unlikely to occur, and a high-quality ink layer having a uniform thickness can be formed, and dimensions A screen gauze having excellent stability and long-term stability can be obtained.

In the present invention, other fibers having the above color values (fibers other than the conjugate fiber of the present invention) may be used in combination, and if the effects of the present invention are not impaired, the above-mentioned fibers may be used. Fibers having no color specification value may be used in combination. From the viewpoints of antihalation effect and various properties such as dimensional stability, it is preferable to use a screen gauze in which the proportion of the conjugate fiber specified in the present invention is 50% by weight or more, more preferably 80% by weight or more, particularly 90% by weight or more. . If the entire screen gauze is configured to satisfy the above colorimetric condition, high-performance printing can be performed using any part of the screen gauze.

The method for producing screen gauze using the core-sheath type composite fiber as described above is not particularly limited. For example, weaving is performed by a known method using the core-sheath type composite fiber as a warp and / or a weft. Is preferred. For example, devising the weaving structure, devising the form of the entangled portion of the yarn, interweaving fibers having different thicknesses, using fibers having relatively excellent flexibility, or appropriately combining them You may. For example, if a twill structure is adopted as the weaving structure, it is possible to stretch the fabric with a relatively high tension. Also, for example, the form of the entangled portion of the fiber,
By setting the entangled state where the bending of the fiber is large, it becomes possible to stretch the fabric at a relatively high tension. Further, for example, by interweaving fibers having different thicknesses, the opening area does not drop much, and the bending of the fibers is increased at the entangled portions of the fibers, so that it is possible to stretch the fabric with high tension. Further, for example, by using a fiber having excellent flexibility, preferably a fiber having a higher strength and a relatively high surface elasticity, it becomes possible to swell at a high tension. From the viewpoints of processability, printing characteristics, abrasion resistance and the like, it is preferable to use a mesh fabric using a composite type composite monofilament.

The structure of the screen gauze is not particularly limited, but in order to perform high-quality printing, the opening area is preferably 35% or more, particularly 37% or more, and more preferably 40% or more. From the viewpoint of dimensional stability, when the tear strength of the screen gauze is X (gf), and among the fibers constituting the screen gauze, the fiber diameter of the fibers arranged along the tearing direction is Y (μm). , X / Y ² is 0.32 or more,
In particular, it is preferably 0.35 or more. When the screen gauze satisfies the opening area and the value of X / Y ² , a printing plate having a high tension (high tension) while having a wide opening area can be obtained. Therefore, high-quality printing of the print image can be performed, and the print image can be used in a state in which the distance between the printing material and the print image is short, so that the expansion rate and distortion of the print image with respect to the printing plate image are small, and the dimensional stability is low. It enables excellent printing with good position accuracy and no printing deviation.

The tear strength was measured according to JIS L 1096.
It is a value measured using an Elmendorf-type tear strength tester in accordance with the D method (Pendulum method). In the present invention, the number of measurement samples is 10 in each of the meridional direction and the weft direction. The tear strength was defined as the arithmetic average of the arithmetic mean of each of the eight measured values excluding the maximum value and the minimum value among the measured values, and the arithmetic average of the history.

The opening area is an opening (a portion where no fiber exists) in each pitch of the weft fibers constituting the screen gauze when the screen gauze is viewed in a plan view.
And the calculated value obtained from the fiber diameter and density of the used fiber. The fiber diameter employs a nominal value, and the density (the number of fibers per inch, expressed in the number of fibers per inch or mesh) employs a value obtained by actually measuring the obtained screen gauze using a densimeter. The fiber diameter of the warp fiber (diameter yarn) is f1 (μm), the fiber diameter of the weft fiber (weft) is f2 (μm), and the density of the warp fiber (density in the weft direction) is M1 (line / inch or mesh). When the density of the weft fibers (the density in the warp direction) is M2 (books / inch or mesh), the opening area S (%) is expressed by the following equation. S = [(25400 / M1-f1). (25400 / M
2-f2)] / [(25400 / M1). (25400
/ M2)] Note that f1 corresponds to the fiber diameter Y in the warp fiber,
f2 corresponds to the fiber diameter Y in the weft fiber.

The tear strength of the screen gauze is preferably 200 gf or more, particularly 300 gf or more, and more preferably 400 gf or more. If the tear strength is less than 200 gf, there is a risk of breaking during high tension gauze depending on the gauze method, and a printing plate with a sufficiently high tension may not be obtained.

The density of the screen gauze is preferably 200 meshes or more, particularly 250 meshes or more, and more preferably 300 meshes or more, since it is easy to print pattern lines arranged at a high density.
The mesh size is preferably 50 mesh or less, particularly 330 mesh or less.

The diameter of the fiber constituting the screen gauze is preferably 45 μm or less, particularly 40 μm or less, more preferably 35 μm or less, and further preferably 33 μm or less, in order to facilitate printing of fine pattern lines. Fiber diameter 35 μm
Below, especially when it is 33 μm or less, 150 μm width, especially 6 μm
A pattern line having a width of 0 μm is easily printed reliably.

Conventionally, in screen printing, higher quality printing can be performed as the opening area is larger. That is, in order to be able to perform high-quality printing in which a printing ink layer of a good form without a dripping is formed of a planar layer having a uniform thickness and sufficient leveling of the ink,
The larger the opening area of the screen gauze constituting the printing plate, the better. However, since a printing plate having a wide opening area cannot usually obtain a high-tension printing plate, in order to obtain a high-quality print image, it is necessary to skive the printing plate away from the printing surface. there were. However, if the printing plate is largely separated from the surface to be printed, it will not be possible to obtain a print image with little distortion while maintaining the dimensions and shape of the printing plate image, or it will be misaligned. Bleeding, and printing of thin lines was impossible.

In particular, it was not possible to obtain a printing plate capable of printing an image containing a thin line with good dimensional reproducibility and with little elongation, displacement and bleeding of the printed image. In order to print a thin line, it is advantageous that the fibers constituting the screen gauze used in the printing plate are thin. However, printing plates made of screen gauze composed of fine fibers generally do not have high tension and have poor dimensional reproducibility. In the present invention, if the above-mentioned value of X / Y ² is satisfied, the problem of the related art can be solved.

The screen gauze of the present invention can be used for pattern printing,
Fine and clear printing can be stably performed in the field of screen printing such as character printing, nameplate printing, and color printing. Above all, precise printing with a line width and a line interval of 150 μm or less can be performed stably with high dimensional accuracy and high quality, and printing with a line width and a line interval of 60 to 100 μm is also possible. Therefore, by applying the present invention to printing of an etching resist ink, a plating resist ink, or the like, it is possible to contribute to a significant reduction in manufacturing cost in manufacturing a fine pattern substrate for electronic equipment. In addition to printing applications, it can be used in various applications such as mesh cloth for filters and substrates for shielding electromagnetic waves.

[0060]

Next, the present invention will be described in more detail with reference to specific examples. It should be noted that the present invention is not limited to the examples described below. In addition, the measuring method of the physical property measured in the Example is shown below.

[Melt viscosity (MV) poise] Measured using a Capillograph 1B manufactured by Toyo Seiki Co., Ltd. under the conditions of 300 ° C. and shear rate γ = 1000 sec ⁻¹ .

[Logarithmic viscosity (ηinh)] 0.1% by weight of a sample was dissolved in pentafluorophenol (60 to 80%).
° C) and a relative viscosity (ηrel) was measured using a Upperode viscometer in a thermostat at 60 ° C, and ηinh = ln (η
rel) / c. Here, c is the polymer concentration (g / dl).

[Color specification value]
Four layers of 0 mm × 20 mm cloths are stacked and measured by a color analyzer (for example, Model C-200S manufactured by Hitachi, Ltd.). If the density or the like of the fabric is different, the colorimetric value is affected, but the colorimetric value can be measured substantially without error by overlapping four or more sheets. From the viewpoint of reducing the measurement error of the color specification value, it is desirable to use a 20 mm × 20 mm cloth,
Even if the size of the fabric is smaller than 20 mm × 20 mm, the measurement can be made with relatively little error if the size is about 10 mm × 10 mm.

[Strength g / d] According to JIS L 1013, using a strong elongation tester model DCS-100 manufactured by Shimadzu Corporation, sample length 20 cm, initial load 0.1 g / d, tensile speed 10 cm / a tensile breaking test under the conditions of
It was determined from the obtained stress-strain curve. The average value of the measured values of five or more points was adopted.

[Elastic modulus g / d] According to JIS L 1013, using a strong elongation tester DCS-100 type manufactured by Shimadzu Corporation, test length 20 cm, initial load 0.1 g / d, tensile speed 10 cm / min A tensile fracture test was performed under the following conditions, and from the obtained stress-strain curve, the elastic modulus was calculated by (w / D) / (ΔL / L). In addition, w is the load (g) when ΔL is elongated, D is the denier (d) of the fiber, ΔL is the length (mm) elongated by the load, and L is the original fiber length.

[Fiber diameter μm] 1000 by scanning electron microscope
A photograph of the side of the fiber magnified twice was taken, the fiber diameter was measured at any 10 points, and the arithmetic average was defined as the fiber diameter.

[Wear resistance (guide wear) times] Six monofilament fibers were passed through each of three comb guides arranged at an angle of 120 degrees using an embracing force tester manufactured by Daiei Scientific Instruments. Then, a load of 1 g / d was applied to each filament, a reciprocating motion was applied at a stroke length of 3 cm and a speed of 95 times / min, and the number of wears (times) at which fluff (peeling, fibrillation) began to occur was measured.

[Wovenability] After weaving using the sample, the fiber surface was observed with an optical microscope, and A was observed when there was substantially no peeling of the sheath component, B when peeling was rarely observed, and peeling sometimes occurred. Was evaluated as C, and D with much peeling was evaluated as D.

[Opening area (OPA)%] This is the area occupancy of the openings (portions where no fibers are present) in each pitch of the weft fibers constituting the screen gauze when the screen gauze is viewed in a plan view. Is calculated by the following equation. S = [(25400 / M1-f1). (25400 / M2
−f2)] / [(25400 / M1) · (25400 / M
2)] Note that the fiber diameter of the warp fiber (diameter yarn) is f1 (μm), the fiber diameter of the weft fiber (weft) is f2 (μm), and the density of the warp fiber (density in the weft direction) is M1 (pieces / inch). , Or mesh), and the density of the weft fibers (the density in the warp direction) is M2 (book / inch or mesh). The fiber diameter was a nominal value, and the density (the number of fibers occupied per inch, expressed by the number of fibers per inch or mesh) was determined by measuring the obtained screen gauze using a densimeter.

[Tear Strength gf] The tear strength is measured according to JIS.
L 1096 This is a value measured using an Elmendorf-type tear strength tester in accordance with the D method (Pendulum method). In the present invention, the number of measurement samples is 10 in each of the longitudinal and weft directions. The tear strength was defined as the arithmetic mean of the eight measured values excluding the maximum value and the minimum value among the ten measured values, and the arithmetic mean of the history.

[Gauze tension mm] Screen gauze and iron frame (external size: 950 mm × 950 mm square: inner shape: 910 m)
mx 910 mm, thickness 30 mm, wall thickness 2 mm), screen gauze was stretched under the following conditions, and the warp direction at the center of the fixed frame by a San Giken tension gauge at each point in time. The average value of each measured value (tension) in the weft direction was measured, and the tension immediately before fixing the gauze (the state where the gauze was pulled and immediately before being fixed to the frame), the tension immediately after the gauze was fixed, and the gauze 7 The tension after a lapse of days was evaluated. Conditions for gauging: Gauging tension: Maximum tension at which the screen gauze does not break when the screen gauze is pulled in the meridian and weft directions by a gauging machine (that is, the tension immediately before breaking). Angle is bias 2
2.5 °) Gauze fixing: After applying tension to the screen gauze and pulling it in the surface direction, a frame for fixing is applied below this and fixed with an adhesive or the like.

[Minimum off-contact mm] A test pattern printing plate is prepared under the following conditions using the gauze 7 days after the gauze obtained by the method described in the above-mentioned method for measuring gauze tension. . Next, the distance (off-contact) between the printing medium (copper-clad board) and the printing plate surface under the following printing conditions
Is changed, and the minimum distance between the printing plate surface and the printing plate on which 100 sheets of continuous printing are performed without causing ink bleeding is set as the minimum off-contact.

1) Plate making conditions Photosensitive emulsion: EX-420 manufactured by Kurita Chemical Co., Ltd. Film thickness: 10 to 11 μm Photomask: T in FIG. 6 indicates line width / line interval = 60/1
A photomask described in FIG. 6 having a stripe pattern of line width / line interval of 100/100 μm at 00 μm and K. Exposure machine: FL-2S manufactured by Ushio Utec Exposure time: 120 K (417 mJ / cm ² ) Development: Water by shower spray Development (water pressure 8kg / c
m ² , time 120 seconds)

2) Printing conditions Printing machine: LS-77A squeegee manufactured by Neurong Seimitsu Co., Ltd. Squeegee made of urethane rubber, hardness 70 °, mounting angle 70 ° Printing pressure: 0.25 mm Lift-up: 0 mm Squeegee speed: 300 mm / sec Ink: Somar ER-70B, viscosity 120po
ise (25 ℃)

[Halation prevention effect (HL) μm]
Continuous printing was performed by the method described in the above-described method of measuring the minimum off-contact (implemented by minimum off-contact), and the pattern lines (line width / line spacing) of the obtained 101 to 103 sheets of printed matter after ink drying were obtained. = 60/100
(μm). First, a photograph is taken by enlarging the state of the pattern lines of the image 200 times with a length measuring device DR-550F manufactured by Dainippon Screen Mfg. Co., Ltd. Then on the photo (5
(cm × 5 cm or more), the maximum value and the minimum line width of 20 or more lines are measured, and the difference between the maximum line width (μm) and the standard line width (60 μm) and the minimum line width (μm), respectively. μm) and the difference between the line width standard value (μm) are calculated, and the average value of the values calculated for a plurality of fibers is evaluated as the HL value. It should be noted that a change in line width at a line width disconnection portion or the like which is considered to be caused by core-sheath peeling or fluffing is excluded. The smaller the HL value, the greater the halation prevention effect.

[Line Fragility] Continuous printing was performed by the method described in the above-mentioned method for measuring minimum off-contact (implemented by minimum off-contact). Observe the state of the pattern lines. The state of the pattern line of the image was enlarged 150 times with a length measuring machine DR-550F manufactured by Dainippon Screen Mfg. Co., Ltd.
A pattern line having a line width of 60 μm and a line width of 100 μm was observed, and line breakage was evaluated according to the following criteria. A: No tear is observed. B: Some tearing is observed. C: Many tears are seen.

[Examples 1 to 5, Comparative Examples 1 to 7] As the A polymer, the structural units (A) and (B) represented by Chemical Formula 3 are 7
3/27 mol% of molten liquid crystalline polyester (melting point 8
0 ° C., melt viscosity 410 poise, ηinh = 4.20 dl
/ G), a linear polymer PPS (see Table 1 for MVb and MPb) as the B polymer, and 73/27 mol% of the structural units (A) and (B) shown in Chemical formula 3 as the C polymer. Polyester (MVc and MVb, see Tables 1 and 2) was used.

First, using a B polymer and a C polymer,
C mixing ratio shown in Tables 1 and 2, respectively: C / (B + C)
Was mixed and kneaded with a twin-screw extruder.
Next, the core component and the sheath component are supplied to separate extruders, and after melting, the following component and Table 1, so that the sheath component ratio R = 0.40,
Under the spinning conditions shown in Table 2, a core-sheath composite fiber of about 9 denier was composite-spun. Nozzle hole diameter: 2r = 0.015 cm Polymer discharge amount per unit hole: Q = 0.015 cm ³ / sec Shear speed: γ = 44300 sec ^-1 Spinning speed: 1100 m / min However, in Comparative Examples 6 and 7, Nozzle hole diameter 2r = 0.02 cm, shear rate γ = 18700 sec ⁻¹
The conditions were adopted.

The obtained monofilament has the general formula (1)
The oil agent described in 5) and the oil agent described in general formula (16) are mixed with 6
The oil agent mixed at a ratio of 0:40 (weight ratio) was applied to the monofilament so as to have a ratio (% by weight) shown in Tables 1 and 2. This monofilament was wound around a perforated bobbin so as to have a density of about 0.55 g / cc and heat-treated. Heat treatment from room temperature to 250 ° C in a nitrogen atmosphere
Over a period of time, the temperature was raised at a constant heating rate, and then from 250 ° C. in a nitrogen atmosphere to a temperature shown in Tables 1 and 2 over 10 hours at a constant heating rate. And Table 2
(In the table, N treatment is a nitrogen atmosphere,
A treatment is an atmosphere in which air is blown into the system and the oxygen concentration is 10% by volume), and heat treatment is performed at the temperatures shown in Tables 1 and 2 for 3 hours to produce fibers.

The obtained monofilament fiber is used for warp and weft to form a plain weave, and the density of the warp is about 25.
A 0-mesh plain woven fabric was obtained. Next, the greige obtained above was put on a tenter and subjected to heat setting by a usual method to obtain a screen gauze. The results are shown in Tables 1 and 2.

[Examples 6 and 7] As the A polymer, 73/27 mol% of the structural units (A) and (B) shown in Chemical Formula 3 above.
Liquid crystalline polyester (MP = 280 ° C., MV
= 410 poise, ηinh = 4.20 dl / g), linear polymer PPS (see Table 1 for MVb and MPb) as the B polymer, and 73 units of the structural units (A) and (B) shown in the above chemical formula 3 as the C polymer. / 27 mol% of a molten liquid crystalline polyester (see Table 1 for MVc and MPc). First, mixed pellets having a C compounding ratio: C / (B + C) shown in Table 1 were kneaded with a twin screw extruder using B polymer and C polymer. Subsequently, the core component and the sheath component were supplied to separate extruders, and after melting, a core-sheath type composite fiber of about 13 denier was spun under the following conditions so that the sheath component ratio R = 0.4. Nozzle hole diameter: 2r = 0.015 cm Polymer discharge amount per unit hole: Q = 0.021 cm ³ / sec Shear speed: γ = 63900 sec ^-1 Spinning speed: 1100 m / min

The same oil agent as in Example 1 was applied to the obtained monofilament in the ratio (% by weight) shown in Table 1. This monofilament was wound around a perforated bobbin so as to have a density of about 0.42 g / cc and heat-treated. In the heat treatment, the temperature is raised from room temperature to 250 ° C. in a nitrogen atmosphere at a constant rate over a period of 5 hours, and then the temperature is increased in a nitrogen atmosphere to 25 ° C.
The temperature was raised from 0 ° C. to the temperature shown in Table 1 at a constant heating rate over 10 hours, and further in the atmosphere shown in Table 1 (in the same table,
N treatment is a nitrogen atmosphere, A treatment is an atmosphere in which air is blown into the system and the oxygen concentration is 10% by volume), and heat treatment is performed at a temperature for 3 hours to produce a conjugate fiber. Manufactured. Table 1 shows the results.

Example 8 Cadmium yellow pigment (Pigment Yellow 35: CI 7711) was used as the B polymer.
7) 0.3% by weight of B polymer to linear P
Except for using PS (MPb 280 ° C, MVb 1170 poise), a composite fiber was produced in the same manner as in Example 6, and a screen gauze was produced. Table 1 shows the results.

[0084]

[Table 1]

[0085]

[Table 2]

In the examples of the present invention, the screen gauze obtained is excellent in various properties such as print clarity and others.
In particular, those obtained by Examples 1 to 4 are colored to a specific color value by a method not using a coloring agent, and since a composite fiber having a very small fiber diameter and a high strength and a high elastic modulus is used, It is excellent in weaving properties, hardly causes fluff and core-sheath peeling even after repeated printing for a long period of time, and has an excellent halation prevention effect, so that it is possible to perform printing for a long time without clear misalignment. .

According to the present invention, it is possible to obtain a screen gauze that can print finer lines clearly and accurately and that does not have a printing deviation even when printing is repeated.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a cross-sectional shape of a conjugate fiber used in the present invention.

FIG. 2 is a schematic diagram showing a fiber cross-sectional structure expected to form a conjugate fiber used in the present invention.

FIG. 3 is a scanning electron micrograph showing an example of the surface shape of a conjugate fiber having gentle undulations on the surface.

FIG. 4 is a schematic view showing an example of a shape of a fiber side surface.

FIG. 5 is a cross-sectional view showing an example of a die that can be used when spinning the core-sheath conjugate fiber.

FIG. 6 is a schematic diagram showing an outline of a test pattern used for a printing test.

[Explanation of symbols]

A: A polymer B: B polymer C: C polymer 1: Fiber 2: Fiber outer peripheral outline a: Line segment a b: Line segment bc: Connected the middle point of line segment a and the middle point of line segment b Center line L: Local maximum point on fiber side surface S: Local minimum point on fiber side surface LL: Distance between L and center line LS: Distance between S and center line T: Portion having pattern of line width / line interval = 60/100 μm K: A portion having a pattern of line width / line interval = 100/100 μm

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tohru Yokomizo 499 Otanicho, Hachioji-shi, Tokyo (72) Inventor Hiroki Sano 994-6, Kamiyoshida, Fujiyoshida-shi, Yamanashi Prefecture

Claims (12)

[Claims] A core component is composed of a molten liquid crystalline polyester (A polymer), and a sheath component is a flexible thermoplastic polymer (B).
Polymer) and molten liquid crystalline polyester (C polymer)
Wherein the compounding ratio of the C polymer is 0.15
A screen gauze made of a core-sheath composite fiber having a colorimetric value shown in the following (1) to (3), which is constituted by a blend of 0.45 to 0.45. 18 ≦ b * ≦ 35 (1) 0.5 ≦ a * ≦ 10 (2) 55 ≦ L * ≦ 80 ... ... (3) (However, b * = 200 [(Y / Y ₀ ) ^1/3 − (Z /
Z ₀ ) ^1/3 ], a * = 500 [(X / X ₀ ) ^1/3 − (Y /
Y ₀ ) ^1/3 ], L * = 116 (Y / Y ₀ ) ^1/3 -16, and X, Y, and Z are tristimulus values of the perfect diffusion surface. ) 2. The screen gauze according to claim 1, wherein the strength of the core-sheath conjugate fiber constituting the screen gauze is 10 g / d or more. 3. The screen gauze according to claim 1, wherein the core-sheath type composite fiber constituting the screen gauze has an elastic modulus of 400 g / d or more. 4. The screen gauze according to claim 1, wherein the content of the coloring agent contained in the core-sheath conjugate fiber constituting the screen gauze is 0.1% by weight or less. . 5. The screen gauze according to claim 1, wherein the flexible thermoplastic polymer constituting the core-sheath type composite fiber is polyphenylene sulfide. 6. The screen gauze according to claim 1, wherein the diameter of the core-sheath type conjugate fiber is 45 μm or less. 7. The screen gauze according to claim 1, wherein the surface of the core-sheath type composite fiber constituting the screen gauze has a gentle undulation. 8. The screen gauze according to claim 1, wherein the screen gauze is a mesh fabric using a core-sheath composite monofilament. 9. The tear strength of the mesh fabric constituting the screen gauze is X (gf), and the yarn diameter of the yarns arranged along the tear direction among the yarns constituting the mesh fabric is Y (μm).
9. The screen gauze according to claim 8, wherein the value of X / Y ² is 0.32 or more and the opening area is 35% or more. 10. The screen gauze according to claim 8, wherein the tear strength is 200 gf or more. 11. The screen gauze according to claim 1, having a density of 200 mesh or more. 12. The compounding ratio of the C polymer is from 0.25 to 0.5.
The screen gauze according to claim 1, which is 4.