JPH041092B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a spun yarn, in which a fiber bundle, for example, a bundle of continuous fibers such as tow or multifilament, is spun directly from the fiber bundle in one step by tension-cutting the fiber bundle. More specifically, a fiber bundle made of acrylic synthetic fibers having crimps is heated to -5 with the crimps maintained.
Crimped by dividing the fiber bundle into a plurality of fiber bundles and cutting them by applying a stretching force and/or shearing force to the fiber bundle while or after contacting with a medium at a temperature of ℃ or lower. The present invention relates to a method for producing a spun yarn, characterized in that a plurality of discontinuous fibers made of acrylic synthetic fibers are formed into a bundle and then continuously fed to each cone of a spinning machine for spinning. A method for producing spun yarn from raw materials in one step is to feed short fibers to a card, divide the carded web into fiber bundles, and feed the fiber bundles to an open-end spinning machine with a rotating spinning chamber. ,
Japanese Patent Publication No. 50-26656, Japanese Patent Publication No. 52-27727, etc. have been proposed. However, since these go through a carding process, it is not possible to create highly uniform fiber bundles in the carding process, which causes neps and hooks, and because the parallelism of single fibers is poor, thread breakage and Spun yarn has many yarn irregularities and yarn defects, making it difficult to obtain spun yarn of good quality. Furthermore, even if the carding process is lengthened and a fiber opening device with a combing function such as a metallic wire is installed, the above-mentioned drawbacks of the carding method cannot be improved much, and the installation area becomes large, and the structure is also small and bulky. It is unsuitable for variety production systems. Furthermore, if brittle fibers, weakly crimped fibers, or fibers with little interfiber stiffness are supplied, there are problems such as fiber breakage and web sag, and there are restrictions on the fibers and their forms that can be used. In the process of producing raw cotton, it is necessary to produce short fibers by cutting the fibers into lengths according to the purpose of spinning. Shrinkage cannot be imparted to the spun yarn during the spinning process. I had a problem. On the other hand, as a method for producing spun yarn in one step from a bundle of continuous fibers such as tow and multifilament,
A method is to produce a spun yarn by feeding the fiber bundle to two sets of rollers with different surface speeds, drawing the fiber bundle, cutting each single fiber constituting the fiber bundle, drafting it to a predetermined weight, and then twisting it. Are known. However, since this method cuts by applying a stretching force at around room temperature (20℃), the cutting is performed with large plastic deformation.
Residual strain occurs inside the fibers, making it impossible to obtain a spun yarn with low shrinkage. ○B Since tension cutting is carried out in the viscoelastic range and at high speed on the spinning machine, the tips of the single fibers bounce back a lot during cutting, are easily disturbed by air currents, have poor thread unevenness, and often break. ○C After cutting, the crimp of the single fibers disappears, so the surface of the spun yarn becomes fluffy. In addition, when connecting the direct spinning method and the open-end spinning method, in the conventional direct spinning method, the fibers are cut after being sufficiently plastically deformed, so the crimp imparted to the raw cotton disappears, and the fibers are cut by the opening roller. Winding and opening were poor and spinning was difficult. On the other hand, in the 48th year of the Special Publication, the crimping process was applied to the tension-cut sliver using a pair of heating gears.
There is a method described in Publication No. 25372. However, it is difficult to provide sufficient crimp with this method;
Even if it is possible, the sliver is crimped to make it fold, so the single fibers are restrained by the crimps, making it difficult for the single fibers to shift. Even if the fibers are separated and opened later using a fiber opening roller, it is not sufficient and yarn breakage and yarn unevenness increase. Furthermore, this method not only cannot sufficiently alleviate the shrinkage that has occurred, but also has many problems such as increased non-uniformity. Further, as a method of compressing a bundle of continuous fibers and supplying the bundle to an open-end spinning machine having a rotating spinning chamber, there is a method described in Japanese Patent Publication No. 51-23611. This is a method in which a bundle of continuous fibers is cut with a pressure roller such as a cutter immediately before the supply pipe of an open-end spinning machine, and then the fibers are separated by airflow generated by the rotation of a rotating spinning chamber. However, when the fibers are cut by a cutter, the ends of the fibers are not separated one by one, and there are many breakages, unevenness, yarn defects, etc., and spun yarn with good quality cannot be obtained. The present invention provides a method to solve the drawbacks of such conventional methods, and in addition to being free of the above drawbacks in the spinning process, it is possible to produce spun yarn with a low to medium shrinkage percentage and of extremely excellent quality. The present invention provides a method for producing spun yarn in one step. An example of a method for producing a bundle of low shrinkage discontinuous fibers from a bundle of continuous fibers is the method described in JP-A-58-60021. In this method, the fiber bundle is cooled to -5°C or lower, and tension-cutting is performed near the elastic region where the elongation is extremely low (hereinafter referred to as the "freezing tension-cutting method"). In that it is possible to efficiently produce bundles of discontinuous fibers with excellent parallelism due to shrinkage, and bundles of discontinuous fibers with low shrinkage and excellent parallelism, which also have crimps after cutting. It is extremely effective. For this reason, it is possible to supply fiber bundles with excellent parallelism and spreadability to the spinning process, which is unimaginable with conventional methods, making it possible to produce spun yarn with excellent spinnability and quality. It became. In the conventional method, when the pre-spinning process and spinning machine are connected,
Due to the difference in production volume, it was limited to machines with high spinning speeds such as open-end spinning machines to produce thick yarns, but with the method of the present invention, the speed of the pre-spinning process can be changed freely, and The slower the speed,
The cooling device is small and requires less installation space.
In addition, since bundles of continuous fibers such as tow can be used, this method is excellent as a method for manufacturing spun yarn for small-lot, high-mix production. That is, in the present invention, a fiber bundle made of crimped acrylic synthetic fiber cooled to -5°C or lower is divided into a plurality of fiber bundles using a divider, cut, and continuously supplied to an existing spinning machine. It is characterized by producing spun yarn in one process from fiber bundles such as tow and multifilament. As the fiber bundle, a continuous fiber bundle such as tow or multifilament is generally used. Acrylic synthetic fibers are particularly preferably used as the continuous fibers. As a bundle of continuous fibers, the fineness of a single fiber is
Multifilaments and tows consisting of 0.1 to 100 denier (d) with a total denier of 30 d to 2,000,000 d are commonly used. Furthermore, it can be applied to a mixture of the above-mentioned continuous fiber bundle and a fiber bundle made of short fibers, or a mixture with other fibers. The lower limit of the temperature of the cooling medium used in the present invention is up to absolute zero, but this poses problems in the cost of the medium used and the equipment, so -5°C to -195°C is preferred. Any cooling medium can be used as long as it has a temperature of -5 DEG C. or lower, and solid, liquid or vaporized gases such as ammonia, carbon dioxide, air, oxygen, nitrogen, fluorocarbon refrigerants, and cryogens can be used. It is also possible to use electrical cooling methods. The time of contact with this cooling medium varies depending on the type of fiber, feeding method, type of medium, temperature, etc., but is generally about 0.1 seconds to 100 minutes. The method of contacting with the cooling medium is not particularly limited as long as the fibers constituting the fiber bundle are kept crimped, but include methods of bringing the fiber bundle into contact with the surface of the cooling medium;
There are methods such as passing the fiber bundle through a gas atmosphere or liquid, and dropping a cooling medium onto the fiber bundle. For cutting, single fibers are cut by applying drawing force and/or shearing force to the fiber bundle while or after contacting the fiber bundle with a medium at −5° C. or lower.
There is no problem in using other cutting forces in addition to these. In addition, the inventors of the present invention proposed JP-A-59
As described in Japanese Patent No. 66519, it is possible to cut the single fibers by providing a crevasse-like tear portion to the single fibers and then applying a drawing force and/or a shearing force. It is preferable that the fiber bundle supplied to the cooling zone is in a state in which single fibers are uniformly divided into a constant width and the thickness is adjusted. The splitting is performed while or after the fiber bundle is brought into contact with a medium at -5°C or lower. The division method is
In the case of multiple multifilaments, it is sufficient to simply provide multiple guides, but in the case of fiber bundles with a very large number of fibers such as tows, the temperature should be kept at -5℃ or below. After cooling, the diagonally oriented single fibers are cut to a predetermined width using a divider and divided into a plurality of fiber bundles while the elongation is very low. At this time, the fiber bundle is cooled and the rigidity of each single fiber increases, so there is less fusion and disturbance of the fiber bundle by cutters, etc., and it can be easily divided. Further, after cutting, it may be divided by a dividing roller or the like in the fleece state. In the present invention, since the tension cutting and spinning are separated, cooling and cutting can be concentrated in one place, which not only simplifies the structure of the cooling device but also reduces cooling costs. On the other hand, in terms of quality, since the speed in the tension cutting region is slow and the number of fiber bundles is increased, there are fewer irregularities caused by bounce of single fibers and turbulence caused by airflow during tension cutting. In addition, by separating tension cutting and spinning in this way, it is also possible to increase the speed of the spinning machine. In this way, the divided fiber bundles are fed to the existing spinning machine by the feed rollers. Further, after being divided, the fiber bundle may be passed through rubbing rollers to improve the cohesiveness of the fiber bundle before being fed to an existing spinning machine. We use a variety of spinning machines including ring spinning machines, rotor-type open-end machines, air vortex open-end machines, bundled spinning methods, air vortex core yarn methods, suction twisting methods, self-twisting methods, and non-twist spinning methods. However, a spinning machine with the highest possible productivity is preferred. Next, the present invention will be explained with reference to the drawings. 1st, 3rd
The figure is a process diagram showing an example of a mode suitable for carrying out the present invention. In FIG. 1, a fiber bundle 1 whose thickness is adjusted while uniformly splitting single fibers into a constant width is fed into a low temperature chamber 7 by a back roller 2 and a delivery roller 8 of the low temperature chamber 7. The delivery roller 8 seals the inlet of the cryostat 7 and the fiber bundle 1.
The outside air contained in the air is compressed. At this time, cooling efficiency is improved by overfeeding the take-up roller 9 at the outlet, and the cryogenic chamber 7
It is possible to prevent fiber breakage due to fiber shrinkage inside.
The fiber bundle 1, which has been sufficiently cooled by meandering through the low-temperature chamber 7 by a rotating roller 10, is compressed of cold air by a take-up roller 9 that seals the outlet. The fiber bundle 1 is brought into contact with a cooling medium of −5° C. or lower in a low-temperature bath 7 to increase the stiffness of the fibers and reduce elongation, and then a drawing force is applied by a middle roller 3 and a break roller 4. The fed fibers are cut to form a bundle of discontinuous fibers, and in this state are divided into a plurality of fiber bundles 12 using a cutter 11. Next, while dividing with the guide 12, the front roller 5 is used to hold the staples with a predetermined weight.
After forming the sliver into a diagram, the tube 14 improves the convergence of the sliver, and the delivery roller 6 feeds the sliver to each cone of the suction-twisting spinning machine 15 to form a spun yarn 16.
That is. FIG. 2 is a plan view of FIG. 1. The third is at the exit of the cryostat, where the cutter 11 divides the fiber bundles into multiple fiber bundles 1, which are then cut into discontinuous fiber bundles, which are continuously fed to each cone of the rotor-type open-end machine 17. This process produces spun yarn. Example 1 A 560,000 denier tow made of polyacrylic synthetic fiber 3D was placed in the apparatus shown in Figure 3 and spun under the following conditions. Crimped state of single fiber Number of crimp 12 (keys/inch) Degree of crimp 12 (%) Overfeed rate 5 (%) Cooling medium Nitrogen gas Temperature inside the cryogenic chamber -100 (℃) Yarn specifications for open end condition Count 1 /15 (Nm) Number of twists: 450 (T/m) Spinning speed: 100 (m/min) As a comparative example, crimps were added to the tow by straight spinning at room temperature (20°C). After that, it was fed to an open-end spinning machine and spun under the same conditions. Furthermore, a staple fiber cut into a 60 mm square of 3D was supplied to the flat card, and the physical properties of the obtained sliver were compared, and the results are shown in the table below.

[Table] In the conventional direct spinning method, the fibers are sufficiently plastically deformed at room temperature (20°C), so the crimp disappears after cutting. The onset of shrinkage is large and a low shrinkage rate cannot be obtained. Furthermore, there are problems such as a decrease in the hook strength and elongation of the single fibers. On the other hand, the sliver obtained by the method of the present invention not only has a low shrinkage rate but also maintains its original crimp. We were able to produce an excellent sliver. Also, open the above sliver continuously.
We installed it on an end spinning machine and compared its process performance and spun yarn. As a result, in the direct spinning method, since there was no crimp, it was difficult to open the fibers, resulting in poor spinning, such as wrapping around the opening roller. Further, even if the yarn is crimped using a stuffing box, only a spun yarn with a high shrinkage rate and a very large amount of fluff can be obtained. In addition, in the carding method, there were more defects such as thread breakage and thread irregularities than defects such as U%, parallelism, and neps of the sliver, and both spinnability and quality were poor. In contrast, the method of the present invention does not have the above-mentioned drawbacks such as wrapping, yarn breakage, yarn unevenness, yarn defects, fuzz, shrinkage rate, etc., and it is possible to obtain a spun yarn with good spinnability and quality. Ta. According to the present invention, after producing a bundle of discontinuous fibers by contacting with a cooling medium of −5° C. or lower,
Since the yarn is continuously supplied to each cone of the spinning machine, (1) By changing the temperature of the cooling medium, it is possible to create a spun yarn with any shrinkage rate from low to medium shrinkage. Manufacture is possible. (2) Even after cutting, it has crimps (almost the same as the original cotton), has excellent parallelism and U%, and has good spinnability and quality of spun yarn. (3) The small footprint and simple structure make it suitable for high-mix, low-volume production. (4) Even when dividing with a cutter, the fibers can be easily divided without fusion or disorder. (5) Furthermore, since the fibers have excellent parallelism, fiber spreading properties, and U%, they can be continuously supplied to spinning machines that do not have a fiber spreading mechanism.

[Brief explanation of drawings]

FIG. 1 is a side view showing the process of implementing the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a side view showing another example of implementing the present invention.

Claims (1)

[Claims] 1 A fiber bundle made of acrylic synthetic fibers having a crimp is brought into contact with a medium at -5°C or lower while maintaining the crimp, or after contacting the fiber bundle, the fiber bundle is divided into a plurality of fibers, and the fiber bundle is divided into a plurality of fibers. The fiber bundle is cut by applying drawing force and/or shearing force to form a bundle of multiple discontinuous fibers made of crimped acrylic synthetic fibers, and then continuously passed through a spinning machine. A method for producing a spun yarn, characterized in that spinning is performed by feeding the yarn to each cone.