JP3449433B2 - Method for producing composite yarn woven or knitted fabric - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite yarn / fiber knitted fabric having excellent mechanical properties, easy handling in knitting and weaving, and good aesthetics when formed into a fabric. It relates to a manufacturing method. More specifically, the present invention relates to a method for producing a composite thread-woven or knitted fabric suitable for materials of clothing similar items such as bulletproof vests, helmets, protective gloves, and aprons that require high mechanical properties and aesthetics. 2. Description of the Related Art Conventionally, wholly aromatic polyamide fibers and wholly aromatic polyester fibers utilize their high strength, heat resistance, chemical resistance and the like to protect high-performance clothing such as uniforms, seat belts, safety belts and the like. Into the field of goods. In recent years, general clothing approximation products having excellent functionality using blended yarns or blended yarns of polyethylene terephthalate fiber or polyamide fiber and the wholly aromatic polyamide fiber or wholly aromatic polyester fiber, for example, sports and leisure suits Is being developed. Recently, polybenzazole having high mechanical properties (eg, tensile strength exceeding 4.0 GPa and high initial elastic modulus exceeding 140 GPa) and high heat resistance and flame retardancy (eg, decomposition start temperature 670C, critical oxygen index 56) Industrial production technology for fibers (PBZ fibers) has been developed. Along with this, the fiber has been attracting attention not only for industrial materials but also as a material for the above-mentioned clothing similar products. [0003] However, polybenzazole fibers generally have a yellow or brown color tone and are immiscible with ordinary dyes, so that they are similar to clothing in terms of color tone. Restricted in use. Conventionally, in order to solve these obstacles, a method of twisting or twisting the polybenzazole fiber with a fiber dyeable or dyed with a normal dye, or entangled with compressed air, etc. Has been considered. However, the dyed dyeable fiber often changes the color tone of the surface periodically or exhibits a marbling tone in the plying yarn or the ply twisted composite yarn. The fabric knitted and woven from the composite yarn having such non-uniform color tone has a problem that a pattern called woodgrain or moiré is easily formed on the surface. In addition, it has been studied to modify the dyeability by a method of copolymerizing a monomer having a dyeing seat or a method of introducing a third component to disrupt the regularity of the fine structure. However, the mechanical properties and thermal properties of the fiber are likely to be sacrificed, and this leads to an increase in raw material costs. An object of the present invention is to provide a composite yarn having a color tone which can be applied to clothing similar products by eliminating these drawbacks derived from the immiscibility of polybenzazole fiber. The present inventors have made intensive studies to achieve the above object, and as a result, have specified a combination of polybenzazole fiber and a fiber which is dyeable to ordinary dyes. The inventors have found that the color tone can be improved without impairing the mechanical properties, and have reached the present invention. That is, in a composite yarn comprising a polybenzazole filament and a dyeable fiber, a twisted polybenzazole filament is used as a core yarn, and the outer periphery thereof is coated with a dye-dyeable fiber. The main purpose is a composite yarn. Hereinafter, the present invention will be described in detail. The polybenzazole fiber (PBZ fiber) used in the present invention is obtained by spinning a dope composed of polybenzoxazole (PBO) or polybenzthiazole polymer (PBT) or a random or block copolymer thereof. And a tensile strength of 4.0 GPa or more and 140 GPa
It is preferable to have the above initial elastic modulus. The fibers which can be dyed in the present invention can be dyed with direct dyes, vat dyes, naphthol dyes, sulfur dyes, disperse dyes, reactive dyes, acid dyes, cationic dyes and the like, and are used for general clothing and industrial purposes. And natural fibers such as cotton, wool, animal hair, hemp, and the like, and synthetic fibers or synthetic fibers such as rayon, cupra, acetate, polyester, polyamide, acrylic, and vinylon. Fibers can be selected. The dyeable fiber may be dyed in advance, and in the case of synthetic fibers such as polyester and polyamide, it is possible to use a dyed yarn obtained by mixing a polymer with a pigment. It is preferable that the fibers dyeable by ordinary dyes used in the present invention have as low a shrinkage property as possible. This is because, when polybenzazole fiber has extremely low heat shrinkage and the composite fiber has high shrinkage, the polybenzazole fiber forms a loop upon heat treatment of the fabric, depending on the degree of the heat shrinkage difference. In the composite yarn of the present invention, it is important to dispose a twisted polybenzazole filament having a high tensile strength and a high initial elastic modulus in a core portion or an inner layer portion. Here, the twisted state means that the twist coefficient is in a range satisfying the following expression. 10 ≦ D ^0.5 × Tw ≦ 80 D; yarn fineness (denier) Tw; number of twists (twice / inch) If the twist coefficient of the polybenzazole long fiber is less than 10, the dyeability is high. At the time of compounding with a fiber, the mechanical properties tend to decrease due to rubbing and damage of the single fibers, depending on the means of compounding. That is, the ratio (retention) of the post-combination strength to the polybenzazole long fiber strength before the combination is likely to decrease. On the other hand, when the twist coefficient is 80
If it exceeds, the mechanical properties decrease due to the twisting of the single fiber.
Therefore, the twist coefficient is preferably set to 10 to 80. The twisted polybenzazole filaments are disposed in the core or the inner layer, and the sheath or the outer layer is coated with a usual dye-dyeable fiber so as to be disposed in the outer layer. The composite yarn can be made to have an arbitrary color tone with the used fiber. In addition, since the polybenzazole fiber is covered with other fibers, the bunching property as a composite yarn is also good, and the frequency of occurrence of troubles such as yarn breakage and catching during winding or weaving of the yarn is high. And the processability is improved. Further, in the use of thermosetting or impregnating with a thermoplastic resin, the adhesiveness is improved as compared with the case where the polybenzazole fiber is used alone. In the composite material of the present invention, the content of the dyeable fiber in the dye is 0.15 to 0.45 (weight ratio).
In this case, a favorable balance of tensile strength, initial elastic modulus, covering degree, convergence and the like can be obtained. When the content ratio of the dyeable fiber in the dye is less than 0.15, the polybenzazole long fiber disposed in the core is partially exposed, and the aesthetic property is impaired. In addition, since the convergence of the composite yarn is reduced, troubles such as yarn breakage and catching during winding or weaving of the yarn are liable to occur. On the other hand, if the content exceeds 0.45, the amount of the polybenzazole fiber decreases, so that it becomes difficult to achieve desired tensile strength and initial elastic modulus. When synthetic fibers such as polyester and polyamide are used as dyeable fibers for ordinary dyes, the mechanical properties and handleability of the composite yarn are improved. In the production of the composite yarn of the present invention, (1) a polybenzazole long fiber is used as a core yarn, and the dyeable long fiber is helically wound around the outer periphery of the core yarn, (2) Polybenzazole filaments are used as a core yarn, and the outer periphery of the filaments is covered with the dyeable short fibers to bind the ends of the short fibers by the action of airflow. An appropriate method can be adopted, such as covering with a short fiber fleece and further winding another dyeable fiber thread around the outside in a coil shape to bind it. FIG. 1 shows an example of an apparatus for producing a composite yarn by the method (1), in which a polybenzazole filament 2 drawn from a bobbin 1 for a core yarn is passed through a yarn guide 3, After being guided to a supply roll 6 through a tension adjusting device 4 and a yarn path guide 5 and passed through a spindle 7 having a hollow inside, it is further wound up on a friction roll through a delivery roll 8 and a yarn path guide 9. To the use bobbin 12. The hollow spindle 7 has a dyeable fiber yarn 10 serving as a sheath yarn.
Is wound, and is rotated by a drive belt running in contact with the lower part of the hollow spindle 7, and the dyeable synthetic fiber yarn 10 pulled out from the sheath bobbin 11 is rotated. Is wound in a coil shape around the outer periphery of the polybenzazole long fiber 1 to form a composite yarn. Hereinafter, each scale used for evaluation in the present invention was determined by the following method. <Fineness> The sample was placed in a standard condition (temperature 22 + 2 degrees, relative humidity 6).
(5 + 2% state) in a test room for 24 hours, and then a 90 m sample was collected using a wrap reel, and its weight was measured and converted to a weight of 9000 m to determine the fineness. <Tensile strength and initial elastic modulus> JISL1013 (198
According to 7.5.1 of 1), a yarn was obtained at a grip interval of 20 cm, a pulling speed of 100% / min, and n = 10 using a Tensilon type testing machine manufactured by Orientec Co., Ltd. in a test room under standard conditions. The strong elongation of the strip was measured. <Mixed state of fiber> The cross section of the composite yarn embedded in resin is cut using a diamond cutter, a micrograph of the cut end is taken, and the dispersion state of the fiber is visually determined. <Judgment of Color Spots on Fabric> The uniformity of the color tone was judged visually. The polybenzazole fiber having a uniform color tone without being exposed on the surface of the cloth was evaluated as ○, the color tone of the polybenzazole fiber was reflected and the color tone was slightly light, and the moire pattern or marbling was evaluated as x. did. <Examples 1 and 2> Using a device shown in FIG. 1, a polybenzoxazole long fiber (PBO fiber) having a fineness of 250 denier is coated with nylon 6 long fiber having a fineness of 75 denier and 36 filaments 300 times per meter using the apparatus shown in FIG. At the number of rotations. The obtained composite yarn was rewound and warped and woven. The obtained fabric was acidified (Fast Navy Blue® CI.
13390) at 100 ° C. for 30 minutes. In Example 1, a nylon processed yarn having a fineness of 75 denier and 36 filaments was used in place of the nylon long fiber. Comparative Example 1 A polybenzoxazole filament having a fineness of 250 denier and a nylon filament having a fineness of 36 denier and 36 filaments were plied at a twist rate of 150 times / m to obtain a composite yarn. Using the composite yarn, weaving and dyeing were performed under the method and conditions described in Example 1, and this was designated as Comparative Example 1. <Example 3> In Example 1, a composite yarn was processed using a polyethylene terephthalate filament having a fineness of 75 denier and 36 filaments instead of the nylon filament, and woven into a fabric. The fabric is treated with a disperse dye (CI Disperse Blue 1, CI 64).
500) using high temperature dyeing (moist heat 120 ° C × 40 minutes)
This was designated as Example 3. <Embodiment 4> The winding section of a normal spinning machine was modified into a cheese winding system, and a swirl nozzle was attached immediately after the front roll. A polyester short fiber (fineness 1 .4 denier, cut length 51m
m) to form a fleece. On the other hand, by supplying a fineness 250 denier polybenzoxazole filaments from directly above the front roll overlapping the center of the fleece, processed pneumatically 4.0 kg / cm ² through them to the swivel nozzle, dyeable fibers Is 30
% Composite yarn was obtained. The composite yarn is woven into a fabric, which is then dispersed with a disperse dye (CI Disperse Bl).
ue1, C.I. High temperature dyeing (wet heat 1)
(20 ° C. × 40 minutes). <Comparative Examples 2-3> Comparative Example 2 in which the polybenzoxazole fiber in Example 1 was replaced with polyparaphenylene terephthalamide fiber having a fineness of 200 denier (trade name of Kevlar 29 Dupont) was used as Comparative Example 2; Comparative Example 3 was a case where the fiber was replaced with a denier ultrahigh molecular weight polyethylene fiber. Table 1 summarizes the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 3. [Table 1] From Table 1, Examples 1 to 3 belonging to the present invention showed good handling properties and process passability of the composite yarn from winding to weaving. Further, the decrease in the strength of the polybenzoxazole fiber due to the compounding was such that it did not pose a practical problem. The fabric obtained by weaving the composite yarn was dyed, but no moiré pattern was observed.
In Example 4 belonging to the present invention, the outer layer was covered with polyester short fibers, so that the obtained fabric had a soft texture and the color tone after dyeing was uniform. On the other hand, Comparative Example 1, which does not belong to the present invention, did not cause single yarn breakage in the rewinding step of the composite yarn, but the fabric after dyeing exhibited a marbling tone. The composite yarns of Comparative Examples 2 and 3 had good handling properties and process passing properties, and the strength of polyparaphenylene terephthalamide fibers or ultra-high molecular weight polyethylene fibers after compounding was small. A moiré pattern or a marbling pattern did not occur on the dyed fabric comprising the composite yarn. However, the strength of the composite yarn was at a lower level than in Examples 1-4. According to the composite yarn of the present invention, a polybenzazole long fiber is disposed in the core, and its high mechanical properties are maintained without being impaired. Since the yarn is covered with the dyeable fiber, there is no yarn crack between the single yarns, and handling of the yarn in the winding process and the weaving process becomes easy. Further, since the inherent color tone of the polybenzazole fiber is concealed by other dyeable fibers, aesthetics can be imparted when the fabric is used. Therefore, the fabric composed of the composite yarn can be used for clothing similar products having both high performance and aesthetics, such as bulletproof vests, helmets, protective gloves, and aprons.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an apparatus showing an example of a compound method used in the present invention. [Description of Signs] 1 bobbin for core yarn 2 polybenzazole long fiber 3 yarn guide 4 tension adjusting device 5 yarn guide 6 supply roll 7 hollow spindle 8 sending-out roll 9 yarn guide 10 dyeable fiber yarn 11 Bobbin for sheath yarn

Claims (1)

(57) [Claim 1] In a composite yarn comprising a polybenzazole filament and a dyeable fiber, a twisted polybenzazole filament is used as a core yarn, and the outer periphery is dyed. A composite yarn coated with a dyeable fiber.