JPH10331048A - Woven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a woven fabric having tenacity and a modulus of elasticity suitable for uses for a screen for precision printing. SOLUTION: This woven fabric is obtained by using a yarn composed of a polybenzoxazole and/or a polybenzothiazole as warp and has tensile strength in the warp direction based on a unit weight of >=6.5 kg.f/g/m<2> and tensile strength in the weft direction of >=6.5 kg.f/g/mm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing screen,
The present invention relates to a woven fabric that can be used for a heat-resistant filter, a filter for filtration, a separator, a safety net, a geotextile, a printed wiring board, an electromagnetic wave shielding transparent mesh, and the like.

[0002]

2. Description of the Related Art Printing screens are manufactured using mesh fabrics such as silk, stainless steel, nylon, and polyester. Silk has problems in strength and dimensional stability. In addition to the problem of elastic recovery and instantaneousness, because it is expensive, nowadays many are made of thermoplastic resins such as polyester and nylon,
In particular, polyester is widely used because of its excellent dimensional stability and low cost.

[0003] However, in the field of printing electronic circuits in recent years, the demand for improving printing accuracy has become more and more severe, and a screen girder made of fiber having high strength and high elastic modulus has been demanded. Super fibers such as fibers having such high strength and high elastic modulus, such as wholly aromatic polyamide fibers and wholly aromatic polyester fibers,
Carbon fibers and the like can be mentioned, but the problem that the wholly aromatic polyamide fiber is poor in dimensional stability due to moisture absorption, the problem that the wholly aromatic polyester fiber is poor in ink permeability, the coatability of the emulsion, etc., Fiber had a problem that it was easily broken.

[0004]

In order to perform precise printing such as printing of an electronic circuit, it is necessary to use a monofilament having a small fineness and to have a large opening area. The strength and elastic modulus of the screen girder using the above-described wholly aromatic polyamide or wholly aromatic polyester fiber depends on the fabric structure, but is insufficient for precision printing and has not yet been put to practical use. is the current situation.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems when the above-mentioned woven fabric made of super fibers, for example, the woven fabric is used as a screen gauze for precision printing, This is based on the tensile strength per unit area in the warp direction and the weft direction of the woven fabric. That is,
The present invention relates to a mesh woven fabric using fibers made of polybenzoxazole and / or polybenzothiazole (hereinafter abbreviated as PBZ) for warp and / or weft yarns. The tensile strength is 6.5 kg · f / g / m ² or more, and the tensile strength in the weft direction is 6.
A woven fabric characterized by being at least 5 kg · f / g / m ² .

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a PBZ according to the present invention will be described. The PBZ is generally a polymer represented by the following formulas a to f.

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[0007]

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[0008]

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[0009]

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[0010]

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[0011]

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In the formula, Ar1, Y, and Ar2 are represented by the following formulas, m, n, o, p, and q are positive integers, between a, b, and c, and between d, e, and f. May optionally be copolymerized.

[0013]

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PBZ preferably used in the present invention
Is a high strength, high modulus fiber can be obtained,
Poly (benzo [1,2-d: 5, polymerized from 3-dihydroxy-4,6-diaminobenzene and terephthalic acid
4-d '] bisoxazole-2,6-diyl-1,4
-Phenylene), poly (benzo [1,2-d: 4,5-d '] bisoxazole-polymerized from 1,4-dihydroxy-2,6-diaminobenzene and terephthalic acid
2,6-diyl-1,4-phenylene), 3-amino-
Poly (2-benzobenzoazole) polymerized from 4-hydroxybenzoic acid, poly (benzo [1,2-d: 5] polymerized from 1,3-diamino-4,6-benzenedithiol and terephthalic acid , 4-d '] bisthiazol-2,
6-diyl-1,4-phenylene), 1,4-diami-
Poly (benzo [1,2-d: 4,5-d '] bisthiazol-2,6-diyl-1,4-phenylene) polymerized from 2,6-benzenedithiol and terephthalic acid; and It is a poly 2,5-benzothiazole polymerized from 3-mercapto 4-aminobenzoic acid.

The PBZ is disclosed in US Pat. No. 4,533,693.
No. 4,772,678 and U.S. Pat. No. 4,847,350.

The fiber comprising PBZ obtained by the above-mentioned known method is first formed into a dope of the PBZ. Examples of the solvent used for forming the dope include cresol and non-oxidizing acids capable of dissolving the PBZ. Examples of the acid include polyphosphoric acid, methanesulfonic acid, and high-concentration sulfuric acid. Or a mixture thereof. Among them, polyphosphoric acid is preferable. In consideration of spinnability and productivity, the concentration of PBZ in the dope is preferably at least 7% by weight, particularly preferably at least 10% by weight, and more preferably at least 14% by weight. Although the upper limit of the concentration of PBZ is not particularly limited, it is 20% by weight in consideration of self-handling properties such as solubility of PBZ in a solvent and dope viscosity.
The following is preferred. The dope is extruded from a nozzle hole, passed through a coagulation bath, solidified, washed with water, dried, and taken off to form a fiber by a known method. The obtained fiber is preferably subjected to a heat treatment in order to impart high strength and high elastic modulus. The heat treatment may be performed by the method described in U.S. Pat. No. 4,581,437.

The PBZ fiber thus obtained has a tensile strength of at least 35 g / denier, particularly at least 40 g / denier, and a tensile modulus of at least 1000 g / denier, especially at least 1500 g / denier. This is preferable for increasing the tensile strength of the mesh fabric.

The fineness of the PBZ fiber can be appropriately set depending on the application. For example, when the woven fabric of the present invention is used for a printing screen (shape) of 10 mesh or more, since it is used as a monofilament, the fiber diameter is 30 to
When used for precision printing, the fiber diameter is preferably 35 to 50 µm. When used as a reinforcement for civil engineering, PBZ in the form of monofilament
The fibers may be used as warp and / or weft, but may also be used in multifilament form. When used in the form of a multifilament, 100% of the multifilament may be composed of PBZ fibers, or may be composed in a form compounded with fibers of another thermoplastic polymer. In the case of the composite form, it is preferable that at least 50% by weight or more of the PBZ fiber is used in order that the tensile strength in the warp direction and the weft direction of the woven fabric satisfy the present invention. The total fineness of the multifilament is preferably from 500 to 10,000 denier, particularly preferably from 1,000 to 3,000 denier.
Furthermore, the woven fabric of the present invention may have a structure in which a monofilament is applied to either one of the warp and the weft. Needless to say, a woven fabric in which both the warp and the weft are composed of the monofilament, both the warp and the weft are composed of the multifilament. It includes all woven fabrics.

Fibers having a high strength and a high elastic modulus usually have a tendency that the fiber surface tends to fibrillate. The PBZ fiber used in the present invention has a high strength and a high elastic modulus, but the fiber surface has a high strength and a high elastic modulus. Is less likely to be fibrillated. Therefore, since fibrillation of the fiber surface hardly occurs at the time of weaving, the fibrillated material is not clogged in the weave, and the present invention is intended as a screen for precision printing which requires a smoother fabric surface. It is suitable when using a woven fabric. In order to impart even more surface smoothness, it is preferable to coat the PBZ fiber with a thermoplastic resin or a polysiloxane and / or a fluorine resin.

Examples of the thermoplastic resin include polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyetherimide; polyetherketone; polyetheretheroketone; A polye;
Tersulfone; polyolefins such as polyethylene and polypropylene; and the like. Among them, it is preferable to use a polymer having a melting point of 120 ° C. or more.
Flame retardants, water repellents, antistatic agents,
Additives such as a static eliminator and an ultraviolet absorber may be contained.

As a method of coating the thermoplastic resin on the PBZ fiber, a melt dipping method in which the PBZ fiber is immersed in a bath of the molten thermoplastic resin, a method of coating the molten thermoplastic resin with the PBZ fiber,
A melt extrusion coating method in which a Z fiber (monofilament) is coated with a resin on the fiber surface through one nozzle hole (coverer
Method), put a resin dissolved in a solvent into a bath,
Dissolution dipping method through BZ fiber can be mentioned,
Any method can be adopted as long as the thermoplastic resin can be uniformly coated on the surface of the PBZ fiber. The PBZ fiber may be coated with the resin in any form of a monofilament or a multifilament. In the case of a multifilament, if a thermoplastic resin is coated around a monofilament which is one of the units constituting the multifilament, a plurality of monofilaments of the unit may be fixed. It is preferable that the unit monofilaments are separated from each other in terms of properties.

The woven fabric woven using the PBZ fiber coated with the thermoplastic resin is bonded to the intersection of the warp and the weft by means of a hot roll press or the like to prevent misalignment of the woven fabric or to improve the strength of the woven fabric. Can be increased.

The polysiloxane is a chain organopolysiloxane having a viscosity at 25 ° C. of 5 to 20,000.
Examples thereof include 0 centipoise dimethylpolysiloxane, diphenylpolysiloxane, methylphenylpolysiloxane, and modified polysiloxane represented by the following formula.

[0024]

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Wherein g and h are integers of 1 or more;
2, R3 and R4 are -CH _3, -OH, -COOH,
_{-NH 2, - (C 2 H} 4 O) j- (C 3 H 6 O) k-H
A group selected from, at least one is a group other than -CH _3.

Polysiloxane is generally used as a surface treatment agent for imparting lubricity, water repellency, oil repellency and the like to fibers and fabrics, and can impart considerable surface smoothness. When coating on the fiber surface, it is used in the form of an emulsion. In order to impart further surface smoothness, it is preferable to crosslink the polysiloxane. It is preferable to use an organic acid salt such as zinc, tin, lead, titanium, potassium, and magnesium as a crosslinking catalyst. The polysiloxane may be emulsified by using a nonionic, anionic or cationic emulsifier, for example, polyoxyethylene alkylphenyl ether,
Quaternary ammonium salts, sodium alkylbenzenesulfonate and the like. The amount of the emulsifier is preferably in the range of 1 to 50 parts by weight based on 100 parts by weight of the solid content of the polysiloxane.

PBZ coated on the surface with polysiloxane
The fibers are provided with not only lubricity and water repellency but also abrasion resistance, and can prevent the occurrence of scum or the like due to weaving or fibrillation at the time of weaving, so that a high-performance fabric can be obtained. A method for applying polysiloxane to PBZ fibers is to discharge a polysiloxane emulsion solution having a fixed concentration onto a traveling yarn at a constant speed from a crow mouth; a yarn is impregnated on a rotating roller partially impregnated with the emulsion solution. And a method in which the yarn is run in the emulsion solution and squeezed with a mangle or the like. A method of coating a desired amount may be selected. A hot-air drier is used to dry the emulsion solution.However, in order to perform the above-mentioned cross-linking of polysiloxane, a drying treatment is performed at a high temperature at the same time as the heat treatment, so it is preferable to use a hot-air drier capable of continuous treatment. .

The amount of the polysiloxane coated on the PBZ fiber may be any amount that can uniformly cover the fiber surface without unevenness, for example, 0.1% by weight or more based on the weight of the fiber. It is preferably from 4 to 20% by weight.

As the above-mentioned fluororesin, tetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FE
P), polychlorotrifluoroethylene (PCFE) and the like. These resins are used in the form of an emulsion to which an emulsifier and the like are added. Specifically, 10 to 50% by weight of an emulsion of a fluororesin is added to the PBZ fiber.
After the deposition, the fiber surface can be coated with a fluorine resin by heating and baking at a temperature of 350 ° C. or more. As the means for attaching to the fiber, the same method as the above-mentioned means for attaching polysiloxane can be used.

Further, it is also possible to apply the above-mentioned polysiloxane and the fluorine-based resin separately in two steps or to apply one step as a mixed solution and heat and calcine them. In such a case, the total amount of the polysiloxane and the fluororesin adhered to the fiber is preferably at least 1% by weight,
0% by weight, especially 3 to 10% by weight, is suitable. The mixing ratio of the polysiloxane and the fluororesin is the former: the latter = 1: 9 to 9: 1 (weight ratio), especially 5: 5 to 5: 5.
It is preferably 9: 1.

The resin may be coated on the fiber surface in the form of a fiber, or may be coated after weaving into a woven fabric.

The woven fabric of the present invention is produced using the above-mentioned monofilament and / or multifilament, and the weaving method is appropriately set according to the application. For example, when intended for use as a printing screen, weaving is performed using PBZ fiber monofilaments as warps and wefts, preset, soaped, heat-processed to a predetermined thickness and mesh number. Can be manufactured. When used as a screen, the weaving density is usually 10 to 600 yarns / inch (10 to 600 warps / wefts).
(600-mesh plain weave), but may be appropriately selected according to the supply amount of the printing ink and the line width of the picture. The preferred weave density is 200 to 500 mesh, and for high precision printing, a weave density of 300 to 450 mesh is preferred.

Then, the screen frame is subjected to a mastication process. The screen frame may be made of any of wood, metal and resin, and an aluminum frame is particularly preferable in view of durability, workability and chemical resistance. Since such a screen has PBZ fiber as a constituent requirement, it can be stretched with a high tension and has little change with time after the stretching. Shorter, leaving overnight is enough. The screen after the sawari process is photosensitive,
Alternatively, it is used for coating a thermosensitive resin or an emulsion. Examples of the photosensitive or heat-sensitive resin include dichromates such as ammonium bichromate, various diazo compounds, and S.I. B. Q-based photosensitizers, acrylic monomer-photosensitizers, etc. are used. As emulsion resins, gelatin, gum arabic, polyvinyl alcohol, vinyl acetate, acrylic resins, and mixtures thereof are used, and emulsifiers, antistatic agents, etc. A photosensitive or heat-sensitive tree or fat emulsion is formed by adding additives such as

After coating the emulsion to the desired thickness by overcoating, the dried screen is finally finished by an exposure or heating step. The pattern baking depends on the emulsion used, but usually a high-pressure mercury lamp, a xenon lamp or the like is used as a light source, and the baking intensity is 1 to 1.5 m.
This is accomplished by exposing at a moderate distance for 2-5 minutes. Unexposed portions are immersed in water and then removed with a water spray or the like.

Since the above-mentioned screen has PBZ fiber as a constituent requirement, the gauze tension can be increased.
Because of its good elastic recovery and dimensional stability, use a monofilament having a fiber diameter of 50 to 70 µm, and more preferably 35 µm or less, and produce a high-density screen of 300 mesh or more, especially 400 mesh or more. Can be.

When the woven fabric of the present invention is used as a reinforcing material for civil engineering, the weaving method is not limited, and the fineness of the PBZ fiber can be appropriately selected according to the purpose. Railway,
When used for embankment embankment, improvement of ground and improvement of mountain slopes such as roads, revetment of riverbanks and coastal areas, especially for soft ground surface treatment, prevention of uneven settlement of submerged levee bodies, prevention of scouring, suction, When used as a filter material, a drain material, and a sandbag, the water permeability of the fabric can be increased by reducing the fabric thickness and the basis weight. Since the woven fabric of the present invention uses the PBZ fiber as described above, it has a high tensile strength, and can reduce the thickness of the woven fabric to increase the water permeability, and further reduce the thickness of the woven fabric. Can withstand the load of sand.

Although the use of the fabric of the present invention has been described above with respect to a printing screen and a reinforcing material for civil engineering, the use of the fabric of the present invention is not limited to these, and a heat-resistant filter, a filtration filter and the like can be used. -Filters, etc.
It can be widely used in the field of industrial materials such as metal, electromagnetic shielding mesh, safety net, printed wiring board material, plastic reinforcement, cement reinforcement, rubber reinforcement, etc.

[0038]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. In addition, each physical property value in an Example is measured and calculated by the following method. (1) Fiber strength A tensile test was performed in accordance with JIS L 1013, the breaking strength was taken as strength, and the slope of a strong elongation curve at 1% elongation was taken as elastic modulus. The measuring instrument was Instron 45.
01 (Instron). (2) Tensile strength of the woven fabric in the warp direction and the weft direction A test piece (width 5 cm, length 20c) cut out from the woven fabric in the warp direction and the weft direction in accordance with JIS L 1096
m) was obtained, and the tensile strength per unit weight was calculated. Note that the same measuring device as that used for measuring the fiber strength was used. (3) Abrasion test The Osa abrasion test was performed using a TM type embracing force tester (manufactured by Daiei Kagaku Kikai). Five monofilaments are passed through three comb guides arranged at an angle of 120 degrees, and a load of 1 g / denier per filament is applied.
The monofilament was abraded by reciprocating the central comb guide at a speed of 95 times / minute with a length of 3 cm, and the number of fluffs generated was measured.

Reference Examples 1 to 3 A stock solution prepared by dissolving 15% by weight of cis-polybenzoxazole having an intrinsic viscosity of 25 dl / g (measured using methanesulfonic acid as a solvent at 30 ° C.) in polyphosphoric acid was heated at 165 ° C. And extruded from a nozzle having a hole diameter of 0.2 mm and 12 holes.
The spun yarn was passed through an air gap of 20 cm and introduced into a coagulation bath using a phosphoric acid solution adjusted to 20 ° C as an extraction medium. Subsequently, the film was washed with water at a speed of 100 m / min, dried, and wound up. The obtained multifilament was subjected to a heat treatment at a temperature of 600 ° C. under tension and divided to obtain a polybenzazol monofilament. By changing the amount of the spinning dope extruded from the nozzle, polybenzazole monofilaments of three types of fineness were obtained. Table 1 shows the physical properties of the monofilament.

Reference Example 4 A polyethylene terephthalate having an intrinsic viscosity of 0.65 dl / g (measured at 30 ° C. in a mixed solvent of phenol / tetrachloroethane and the like) at 290 ° C. with a pore size of 0.25 mm
It was melt extruded from a hole nozzle and wound up at a speed of 1000 m / min. A hot roller at 75 ° C.
Stretching is performed using a hot plate at 150 ° C. (stretching ratio: 3.5 times), separated, and polyethylene terephthalate.
A tomonofilament was obtained. Table 1 shows the physical properties of the monofilament.

Reference Example 5 Thermotropic polyester [Vectra A910RX: manufactured by Celanese Corporation] having an intrinsic viscosity of 5.21 dl / g (measured at 70 ° C. using pentafluorophenol as a solvent) was used.
It was melt-extruded from a nozzle having a hole diameter of 0.15 mm and 12 holes at 20 ° C. and wound up at a speed of 1000 m / min. The obtained yarn was subjected to a heat treatment at 270 ° C. in a nitrogen atmosphere and separated to obtain a polyester monofilament. Table 1 shows the physical properties of the monofilament.

[0042]

[Table 1]

Example 1 The polybenzazole monofilament obtained in Reference Example 2 was used for warp and weft, and woven into 300 mesh with a Sulzer loom to obtain a mesh fabric. The weaving property was good, and no generation of fibrillated substances such as scum was observed on hem and heald. The strength in the warp direction and the weft direction of the mesh fabric was measured, and the tensile strength per unit weight was calculated.
Table 2 shows the results. This mesh fabric is stretched on an aluminum frame, coated with a polyvinyl alcohol-vinyl acetate photosensitive emulsion (NK-14, manufactured by Kaley), dried, exposed to a high-pressure mercury lamp, and patterned with a line width of 80 μm. The unexposed portions were washed away with water to form a screen. Using this screen, 30 patterns were formed on a glass plate.
After printing 00 times, the pattern having a line width of 80 μm was printed clearly with almost no deviation.

Example 2 The surface of the polybenzazole monofilament obtained in Reference Example 1 was coated with a 20% by weight emulsion of silicone oil (manufactured by Shin-Etsu Silicone Co., Ltd.). It was introduced into a hollow dryer and dried and heat-treated. Using a polybenzazole monofilament coated with silicone oil for warp and weft, a 350 mesh woven fabric was produced in the same manner as in Example 1. Table 2 shows the tensile strength of the mesh fabric in the warp direction and the weft direction. Then, a photosensitive emulsion was applied and exposed in the same manner as in Example 1, and a pattern having a line width of 60 μm was printed and screened.
Was prepared. When a pattern was printed 3000 times on a glass plate using this screen, a pattern having a line width of 60 μm was printed clearly with almost no shift.

Example 3 In Example 2, a 20% by weight liquid of an agent containing a tetrafluoroethylene resin-containing emulsion and a curing agent for the resin [JLK 023, manufactured by Acheson Japan Ltd.] was used as a coating agent. And dried and heat-treated at 370 ° C. Then, a 350-mesh woven fabric was produced in the same manner as in Example 1, except that the polybenzazole monofilament coated with the fluororesin was used for the warp and the weft.
Table 2 shows the tensile strength of the mesh fabric in the warp direction and the weft direction. Then, a light-sensitive emulsion was applied and exposed in the same manner as in Example 1, and a pattern having a line width of 60 μm was printed to form a screen. When a pattern was printed 3000 times on a glass plate using this screen, the line width was 60 μm.
Was printed clearly with almost no shift in the pattern.

Comparative Example 1 A mesh fabric was produced in the same manner as in Example 1 except that the polyethylene terephthalate monofilament obtained in Reference Example 4 was used. Although the weavability was good, the strength of the obtained woven fabric was weak and the elongation was large. Table 2 shows the physical properties of the woven fabric. A screen was prepared and printed from the mesh fabric in the same manner as in Example 1, but the pattern was printed with a shift in pattern due to high elongation.

Comparative Example 2 A mesh fabric was produced in the same manner as in Example 1 except that the polyester monofilament obtained in Reference Example 5 was used. During weaving, scum (fibrillated material) was accumulated on the sack. A screen was produced from this mesh fabric in the same manner as in Example 1. However, scum was also incorporated in the screen, and only a low-quality fabric was obtained.
Further printing was carried out, but only the line width was crushed due to the presence of scum.

[0048]

[Table 2]

[0049]

The woven fabric of the present invention has a high tensile strength in the warp direction and the weft direction, and also has a high tensile strength of the fibers constituting the woven fabric, and can be suitably used for, for example, screens for precision printing. . In addition, when used as a reinforcing material for civil engineering, the material is lightweight, strong, and excellent in water permeability.

Claims (6)

[Claims] 1. A woven fabric comprising a fiber made of polybenzoxazole and / or polybenzthiazole for warp and / or weft, having a tensile strength in the warp direction per unit weight of 6.5 kg. f / g / m ² or more, fabric tensile strength of the weft direction and wherein the at 6.5kg · f / g / m ² or more. 2. The woven fabric according to claim 1, wherein the warp and / or weft are monofilaments and / or multifilaments made of polybenzoxazole and / or polybenzthiazole. 3. The woven fabric according to claim 1, which is a fiber comprising polybenzoxazole and / or polybenzthiazole coated with a thermoplastic resin. 4. The woven fabric according to claim 1, wherein the fibers are fibers made of polybenzoxazole and / or polybenzthiazole coated with polysiloxane and / or a fluorine resin. . 5. The woven fabric according to claim 1, which is a screen for printing. 6. The woven fabric according to claim 1, which is a reinforcing material for civil engineering.