METHOD AND APPARATUS FOR SPREADING OR DIVIDING YARN, TOW OR THE LIKE
United States Patent 3657871
A method of spreading or dividing into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the filaments. The material is continuously passed through and in contact with a narrow passage of a first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode. The second electrode is spaced from and is in alignment with the first electrode and is also spaced from the narrow passage in such a manner that the individual filaments divided or spread out of the multifilament material do not contact the second electrode.
US Patent References:
Process for spreading or dividing textile materials
Niina et al. - December 1967 - 3358436
Process for spreading or dividing textile materials
Niina et al. - December 1967 - 3358436
Inventors:
Uchiyama, Sei (Takatsuki, JA)
Kaku, Eiichi (Takatsuki, JA)
Kobayashi, Masahiro (Takatsuki, JA)
Zoda, Takamichi (Takatsuki, JA)
Fujimoto, Shunsaku (Shodo-gun, JA)
Kaku, Eiichi (Takatsuki, JA)
Kobayashi, Masahiro (Takatsuki, JA)
Zoda, Takamichi (Takatsuki, JA)
Fujimoto, Shunsaku (Shodo-gun, JA)
Application Number:
05/020603
Publication Date:
04/25/1972
Filing Date:
03/18/1970
View Patent Images:
Export Citation:
Assignee:
Toyo Boseki Kabushiki Kaisha (Osaka, JA)
Primary Class:
Other Classes:
57/352, 57/244, 57/309, 57/332, 28/282
International Classes:
B65H51/01; D01D7/00; D01D10/04; B65H51/005; D01D10/00; D01H1/00
Field of Search:
57/164,156,157,34R,90 28/75,1R
Primary Examiner:
Petrakes, John
Claims:
What we claim is
1. A method of spreading or dividing into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the filaments, which comprises continuously passing the textile material through and in contact with a narrow passage of a first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode, said second electrode being spaced from but in alignment with the first electrode and being spaced also from the passageway of the continuous multifilament textile material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode; said first electrode being a narrow tubular member provided with a narrow passage through and in contact with which the textile material is passed toward the second electrode.
2. A method of spreading or dividing into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the filaments, which comprises continuously passing the textile material through and in contact with a narrow passage of a first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode, said second electrode being spaced from but in alignment with the first electrode and being a hollow frustoconical member diverging in the direction of travel of the textile material so as to be spaced from the passageway of the continuous multifilament textile material in such a manner that the individual divided or spread out of the multifilament material would not contact the second electrode.
3. An apparatus for separating or dividing or spreading into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the individual filaments, which comprises a first electrode having a narrow passage through and in contact with which the textile material is passed, a second electrode having a potential difference of at least 500 volts from the first electrode and through which the textile material discharged from the first electrode is passed, said second electrode being spaced from but in alignment with the first electrode and being spaced also from the passageway of the continuous multifilament textile material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode, said first electrode being a narrow tubular member provided with a narrow passage through and in contact with which the textile material is passed toward the second electrode.
4. An apparatus for separating or dividing or spreading into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of individual filaments, which comprises a first electrode having a narrow passage through and in contact with which the textile material is passed, a second electrode having a potential difference of at least 500 volts from the first electrode and through which the textile material discharged from the first electrode is passed, said second electrode being spaced from but in alignment with the first electrode and being a hollow frustoconical member diverging in the direction of the travel of the textile material so as to be spaced from the passageway of the continuous multifilament textile material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode.
1. A method of spreading or dividing into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the filaments, which comprises continuously passing the textile material through and in contact with a narrow passage of a first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode, said second electrode being spaced from but in alignment with the first electrode and being spaced also from the passageway of the continuous multifilament textile material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode; said first electrode being a narrow tubular member provided with a narrow passage through and in contact with which the textile material is passed toward the second electrode.
2. A method of spreading or dividing into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the filaments, which comprises continuously passing the textile material through and in contact with a narrow passage of a first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode, said second electrode being spaced from but in alignment with the first electrode and being a hollow frustoconical member diverging in the direction of travel of the textile material so as to be spaced from the passageway of the continuous multifilament textile material in such a manner that the individual divided or spread out of the multifilament material would not contact the second electrode.
3. An apparatus for separating or dividing or spreading into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of the individual filaments, which comprises a first electrode having a narrow passage through and in contact with which the textile material is passed, a second electrode having a potential difference of at least 500 volts from the first electrode and through which the textile material discharged from the first electrode is passed, said second electrode being spaced from but in alignment with the first electrode and being spaced also from the passageway of the continuous multifilament textile material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode, said first electrode being a narrow tubular member provided with a narrow passage through and in contact with which the textile material is passed toward the second electrode.
4. An apparatus for separating or dividing or spreading into individual filaments a solid substantially non-twisted continuous multifilament textile material consisting of a plurality of individual filaments, which comprises a first electrode having a narrow passage through and in contact with which the textile material is passed, a second electrode having a potential difference of at least 500 volts from the first electrode and through which the textile material discharged from the first electrode is passed, said second electrode being spaced from but in alignment with the first electrode and being a hollow frustoconical member diverging in the direction of the travel of the textile material so as to be spaced from the passageway of the continuous multifilament textile material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode.
Description:
This invention relates to a method and apparatus for spreading or dividing a substantially non-twisted yarn, tow, strand or the like consisting of a plurality of continuous monofilaments.
It is known to spread or divide a substantially non-twisted yarn, tow, strand or the like (consisting of a plurality of continuous monofilaments) into the individual filaments. For this purpose, there have been proposed various mechanical, pneumatic, supersonic and electrical systems, among which an electrical system is known to be most effective.
However, conventional electrical systems have various drawbacks. Thus, according to U.S. Pat. No. 3,358,436 dated Dec. 19, 1967 which discloses a typical electric system of this kind, a multifilament yarn is imparted with electrical conductivity by the application of water, and then a high electric current of at least 5,000 volts is applied to the wet yarn to spread the same into individual filaments. This method can be applied to any kind of fibers and assures stable and high speed operation. However, this method is dangerous in actual practice because an electrode at a dangerously high voltage must be used. The use of such high voltage necessiates careful insulation of various parts of the apparatus. Further, there is a danger of causing damages to the fibers due to passage of electric current therethrough. Moreover, the method has another disadvantage that water supply means for imparting electric conductivity to the yarn must be installed.
Accordingly, an object of the present invention is to provide a novel method and apparatus for dividing or spreading a multifilament yarn, tow or the like which can be satisfactorily put into practice with much lower voltage.
Another object of the invention is to provide a method and apparatus of the kind mentioned above which does not require any special water supply means and can be put into practice under the usual textile mill atmosphere with a relative humidity of 60 - 80 percent.
A further object of the invention is to provide a method and apparatus of the kind mentioned above which does not cause damages to fibers at the time of treatment and which consumes a less amount of electric power.
Other objects of this invention will become apparent from the following description.
According to the present invention, a substantially non-twisted continuous multifilament material in the form of yarn, strand, tow or the like is passed through a narrow passage of a first electrode so as to be in contact with the inner side of the first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode, said second electrode being spaced from the first electrode and spaced also from the passageway of the continuous multifilament material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode. During the passage through and in contact with the first electrode the multifilament material is electrically charged. When the electrically charged material is subsequently passed through the second electrode the individual monofilaments constituting the multifilament material are pulled or displaced outwardly toward the inner wall of the second electrode so that the multifilament material is divided or spread into individual monofilaments, which may be taken-up separately or treated in a manner known in the art (refer, for example, to U.S. Pat. No. 3,358,436).
The invention may be applied to any kind (inorganic or organic, hydrophilic or hydrophobic) of textile material provided that it is in the form of a solid continuous substantially non-twisted material consisting of a plurality of monofilaments, typical example of such material being multifilament yarn or tow which is well known in the art.
The invention will be further explained by referring to the accompanying drawings wherein:
FIG. 1 is a schematic front view of an apparatus embodying this invention;
FIG. 2 is an enlarged longitudinal section of the electrodes shown in FIG. 1;
FIG. 3 is a view similar to FIG. 2 but showing another form of electrodes;
FIG. 4 is a view similar to FIG. 2 but showing still another form of electrodes; and
FIG. 5 is a schematic front view of an apparatus showing another embodiment of the invention.
Referring to the drawings, particularly FIG. 1, indicated with the numeral 1 is a package of a continuous multifilament yarn 2. Usually, such yarn is produced by melt, wet or dry spinning a fiber-forming material into monofilaments, which are stretched for molecular orientation and then wound up to form the package 1. Usually, there still remains on the yarn 2 a textile processing agent, such as anti-static agent, lubricating agent, emulsifying agent, etc. which has been applied to the filaments during the spinning operation. The yarn 2 of the package 1, without having any further preparatory treatment applied thereto, is withdrawn by feed rolls 3 through tension means 4 and passed through a first electrode 5 and then through a second electrode 6. The first electrode 5 has an extremely narrow passage through and in contact of which the yarn 2 is passed. Preferably, the first electrode 5 is in a small tubular form as shown. A positive voltage of at least 500 volts is applied to the first electrode. In the embodiment shown in FIGS. 1 and 2, the second electrode 6 is aligned with but spaced from the lower end of the first electrode 5 and is in the form of a hollow frustoconical body diverging in the direction of travel of the yarn 2. The second electrode 6 is grounded as shown in FIG. 1. Alternatively, the first electrode may be grounded while a positive voltage is applied to the second electrode, or one electrode may have a positive voltage and the other a negative voltage applied thereto. In any case, it is necessary that there be a potential difference of at least 500 volts between the two electrodes.
The second electrode may take any other suitable form provided that the inner wall is properly spaced from the passageway of the yarn 2. Thus, for example, the second electrode may be in the form of a ring-like electrode 8 shown in FIG. 3. It is possible to arrange a plurality of such ring-like electrodes in series. The second electrode may also be in the form of a coil through which the yarn is passed. Alternatively, as shown in FIG. 4, the second electrode may consist of a plurality of plate-like electrodes 9, 9 or bar-like electrodes arranged to define a yarn passageway therebetween. In any case the inner wall of the second electrode should be properly spaced from the yarn so as to allow outward spreading of the yarn and to prevent the spread filaments from contacting the second electrode.
In practice, however, it is most advantageous to employ a hollow frustoconical body increasing in diameter in the direction of travel of yarn as shown in FIGS. 1 and 2.
The distance between the first and second electrodes may vary depending on the working voltage, but advantageously it should be as short as possible provided that there will be no discharge taking place between the two electrodes.
The first tubular electrode 5 should be as narrow as possible in inner diameter. For a yarn of less than 500 deniers, for example, the inner diameter of the first electrode should be 2 mm. or less, and for a thick sliver or tow, it may sometimes be 5 mm. or more depending upon the thickness. The length of the first electrode is not critical but relatively great (e.g., 3 - 15 mm.).
When the second electrode is frustoconical, the dimension may be suitably designed. By way of example, the inclination is 35°, the diameter of the opening at the maximum diameter portion i.e., bottom is 45 mm., and the distance from the first electrode is 1 mm. at the closest region. A positive voltage of at least 500 volts, preferably 2,000 - 5,000 volts is applied to the first electrode, while the second electrode is grounded.
With the arrangement as explained above, when a multifilament yarn is continuously passed through the apparatus under a suitable tension, the monofilaments constituting the yarn are electrically charged during the passage through the first electrode. Due to the repulsion between the monofilaments and the action of the electric field established by the first and second electrodes or the attracting action of the second electrode on the individual filaments, the yarn is divided, spread or separated into individual monofilaments within the second electrode even if the voltage is relatively low. Generally, the spread filaments take the shape of a spindle as well shown in the drawings. The separated individual monofilaments are deformed at the roller 7 into a sheet form and are withdrawn therefrom in such a shape that the filaments are spread into a sheet form.
When the two plate-like electrodes 9, 9 arranged as shown in FIG. 4 are used as the second electrode, the yarn will be spread to assume a shape like a sheet rather than a spindle shape.
In order to facilitate the spreading it is preferable to make the yarn feed rate at the feed rollers a little excessive. This overfeed, however, is not always necessary.
The monofilaments spread in this way may be used for various applications which are known in the art, such as for the production of non-woven fabrics, various blended yarns, etc. (refer, for example, to U.S. Pat. No. 3,358,436).
It is also possible to arrange two or more sets of the apparatus side by side as shown in FIG. 5. Separate yarns 2,2 of different kind are passed through their respective electrodes and the respective spread monofilaments are guided through respective guide rings 13,13 to common rollers 7 at which there are overlapped each other. The overlapped monofilament assembly may be then twisted together by a twister 10 and wound on a bobbin 11 to obtain a yarn 12 in which the different filaments are blended together. In this case it is possible to use two or more kinds of yarns different in chemical and/or physical properties such as dyeability, hygroscopicity and shrinkability in accordance with the desired object to improve the properties of filament yarn. In this case, in order to assure more effective blending of filaments, it is preferable that the tension applied by the tension means 4 is so adjusted as to make the elongations of both yarns equal to each other. The spreading widths of the respective yarns may be made equal to each other by utilizing the ring-like guides 13 prior to overlapping them together at the rolls 7,7.
The method of this invention is applicable to any kind of multifilament yarn. If desired, the apparatus may be combined with a conventional pneumatic or supersonic wave apparatus known to spread a multifilament yarn into monofilaments. Further according to this invention, since spreading is effected not only by a mere repulsion due to electric charge but also by the mutual action of the first and second electrodes, it can be carried out with a relatively low voltage. Therefore, safety is high. Further, since there is no need of providing water supply means, the apparatus is simple and free from contamination, and as long as the yarn contains only the ordinary textile processing agents including an anti-static agent deposited thereon in the course of spinning operation, there is no need of effecting any special pretreatment such as cleaning or wetting before subjecting the yarn to the spreading treatment of this invention. Moreover, according to this invention, there is no need of specially adjusting the humidity provided that the atmosphere is that of the ordinary textile mill. Further, since yarn spreading does not occur between the first electrode and the feed rollers, there is no danger of the fiber being damaged by being rubbed as the yarn passes through the narrow passage of the first electrode.
The following examples illustrate the invention.
EXAMPLE 1
A nylon multifilament yarn (70 deniers, 24 monofilaments) having a twist of two turns per meter was passed through an apparatus as shown in FIG. 1 in an atmosphere of a relative humidity of 70 percent, under a tension of 0.01 gram/denier and at a speed of 700 meters per minute. In the apparatus, the first electrode 5 was 5 mm. in length and formed with a narrow passage of an inner diameter of 0.7 mm. The frustoconical second electrode 6 had a height of 10 mm., top diameter 6 mm. and bottom diameter of 10 mm. The lower end of the first electrode was arranged to lie on the top surface of the second electrode. The voltage of the first electrode was 4,000 volts, while the second electrode was grounded. The rolls 7 were placed at a distance of 30 cm. from the bottom of the second electrode. The spread monofilaments were flattened at the rolls 7 at which the maximum spreading width was 47 mm.
EXAMPLE 2
A non-twisted viscose rayon multifilament yarn (60 deniers, 20 multifilaments) was passed through an apparatus as shown in FIG. 1 in an atmosphere of a relative humidity of 70 percent and at a speed of 100 meters per minute (overfeed at the feed rollers 3 was 0.5 percent). In the apparatus, the first electrode 5 was 10 mm. in length and had a passage of an inner diameter of 0.7 mm. The frustoconical second electrode 6 had a height of 10 mm., top diameter of 6 mm. and bottom diameter of 12 mm. The distance between the lower end of the first electrode and top surface of the second electrode was 1 mm. The spread monofilaments were flattened at the rolls 7 at which the maximum spreading width was 53 mm. The rolls 7 were placed at a distance of 40 cm. from the bottom of the second electrode.
It is known to spread or divide a substantially non-twisted yarn, tow, strand or the like (consisting of a plurality of continuous monofilaments) into the individual filaments. For this purpose, there have been proposed various mechanical, pneumatic, supersonic and electrical systems, among which an electrical system is known to be most effective.
However, conventional electrical systems have various drawbacks. Thus, according to U.S. Pat. No. 3,358,436 dated Dec. 19, 1967 which discloses a typical electric system of this kind, a multifilament yarn is imparted with electrical conductivity by the application of water, and then a high electric current of at least 5,000 volts is applied to the wet yarn to spread the same into individual filaments. This method can be applied to any kind of fibers and assures stable and high speed operation. However, this method is dangerous in actual practice because an electrode at a dangerously high voltage must be used. The use of such high voltage necessiates careful insulation of various parts of the apparatus. Further, there is a danger of causing damages to the fibers due to passage of electric current therethrough. Moreover, the method has another disadvantage that water supply means for imparting electric conductivity to the yarn must be installed.
Accordingly, an object of the present invention is to provide a novel method and apparatus for dividing or spreading a multifilament yarn, tow or the like which can be satisfactorily put into practice with much lower voltage.
Another object of the invention is to provide a method and apparatus of the kind mentioned above which does not require any special water supply means and can be put into practice under the usual textile mill atmosphere with a relative humidity of 60 - 80 percent.
A further object of the invention is to provide a method and apparatus of the kind mentioned above which does not cause damages to fibers at the time of treatment and which consumes a less amount of electric power.
Other objects of this invention will become apparent from the following description.
According to the present invention, a substantially non-twisted continuous multifilament material in the form of yarn, strand, tow or the like is passed through a narrow passage of a first electrode so as to be in contact with the inner side of the first electrode and then through a second electrode having a potential difference of at least 500 volts from the first electrode, said second electrode being spaced from the first electrode and spaced also from the passageway of the continuous multifilament material in such a manner that the individual filaments divided or spread out of the multifilament material would not contact the second electrode. During the passage through and in contact with the first electrode the multifilament material is electrically charged. When the electrically charged material is subsequently passed through the second electrode the individual monofilaments constituting the multifilament material are pulled or displaced outwardly toward the inner wall of the second electrode so that the multifilament material is divided or spread into individual monofilaments, which may be taken-up separately or treated in a manner known in the art (refer, for example, to U.S. Pat. No. 3,358,436).
The invention may be applied to any kind (inorganic or organic, hydrophilic or hydrophobic) of textile material provided that it is in the form of a solid continuous substantially non-twisted material consisting of a plurality of monofilaments, typical example of such material being multifilament yarn or tow which is well known in the art.
The invention will be further explained by referring to the accompanying drawings wherein:
FIG. 1 is a schematic front view of an apparatus embodying this invention;
FIG. 2 is an enlarged longitudinal section of the electrodes shown in FIG. 1;
FIG. 3 is a view similar to FIG. 2 but showing another form of electrodes;
FIG. 4 is a view similar to FIG. 2 but showing still another form of electrodes; and
FIG. 5 is a schematic front view of an apparatus showing another embodiment of the invention.
Referring to the drawings, particularly FIG. 1, indicated with the numeral 1 is a package of a continuous multifilament yarn 2. Usually, such yarn is produced by melt, wet or dry spinning a fiber-forming material into monofilaments, which are stretched for molecular orientation and then wound up to form the package 1. Usually, there still remains on the yarn 2 a textile processing agent, such as anti-static agent, lubricating agent, emulsifying agent, etc. which has been applied to the filaments during the spinning operation. The yarn 2 of the package 1, without having any further preparatory treatment applied thereto, is withdrawn by feed rolls 3 through tension means 4 and passed through a first electrode 5 and then through a second electrode 6. The first electrode 5 has an extremely narrow passage through and in contact of which the yarn 2 is passed. Preferably, the first electrode 5 is in a small tubular form as shown. A positive voltage of at least 500 volts is applied to the first electrode. In the embodiment shown in FIGS. 1 and 2, the second electrode 6 is aligned with but spaced from the lower end of the first electrode 5 and is in the form of a hollow frustoconical body diverging in the direction of travel of the yarn 2. The second electrode 6 is grounded as shown in FIG. 1. Alternatively, the first electrode may be grounded while a positive voltage is applied to the second electrode, or one electrode may have a positive voltage and the other a negative voltage applied thereto. In any case, it is necessary that there be a potential difference of at least 500 volts between the two electrodes.
The second electrode may take any other suitable form provided that the inner wall is properly spaced from the passageway of the yarn 2. Thus, for example, the second electrode may be in the form of a ring-like electrode 8 shown in FIG. 3. It is possible to arrange a plurality of such ring-like electrodes in series. The second electrode may also be in the form of a coil through which the yarn is passed. Alternatively, as shown in FIG. 4, the second electrode may consist of a plurality of plate-like electrodes 9, 9 or bar-like electrodes arranged to define a yarn passageway therebetween. In any case the inner wall of the second electrode should be properly spaced from the yarn so as to allow outward spreading of the yarn and to prevent the spread filaments from contacting the second electrode.
In practice, however, it is most advantageous to employ a hollow frustoconical body increasing in diameter in the direction of travel of yarn as shown in FIGS. 1 and 2.
The distance between the first and second electrodes may vary depending on the working voltage, but advantageously it should be as short as possible provided that there will be no discharge taking place between the two electrodes.
The first tubular electrode 5 should be as narrow as possible in inner diameter. For a yarn of less than 500 deniers, for example, the inner diameter of the first electrode should be 2 mm. or less, and for a thick sliver or tow, it may sometimes be 5 mm. or more depending upon the thickness. The length of the first electrode is not critical but relatively great (e.g., 3 - 15 mm.).
When the second electrode is frustoconical, the dimension may be suitably designed. By way of example, the inclination is 35°, the diameter of the opening at the maximum diameter portion i.e., bottom is 45 mm., and the distance from the first electrode is 1 mm. at the closest region. A positive voltage of at least 500 volts, preferably 2,000 - 5,000 volts is applied to the first electrode, while the second electrode is grounded.
With the arrangement as explained above, when a multifilament yarn is continuously passed through the apparatus under a suitable tension, the monofilaments constituting the yarn are electrically charged during the passage through the first electrode. Due to the repulsion between the monofilaments and the action of the electric field established by the first and second electrodes or the attracting action of the second electrode on the individual filaments, the yarn is divided, spread or separated into individual monofilaments within the second electrode even if the voltage is relatively low. Generally, the spread filaments take the shape of a spindle as well shown in the drawings. The separated individual monofilaments are deformed at the roller 7 into a sheet form and are withdrawn therefrom in such a shape that the filaments are spread into a sheet form.
When the two plate-like electrodes 9, 9 arranged as shown in FIG. 4 are used as the second electrode, the yarn will be spread to assume a shape like a sheet rather than a spindle shape.
In order to facilitate the spreading it is preferable to make the yarn feed rate at the feed rollers a little excessive. This overfeed, however, is not always necessary.
The monofilaments spread in this way may be used for various applications which are known in the art, such as for the production of non-woven fabrics, various blended yarns, etc. (refer, for example, to U.S. Pat. No. 3,358,436).
It is also possible to arrange two or more sets of the apparatus side by side as shown in FIG. 5. Separate yarns 2,2 of different kind are passed through their respective electrodes and the respective spread monofilaments are guided through respective guide rings 13,13 to common rollers 7 at which there are overlapped each other. The overlapped monofilament assembly may be then twisted together by a twister 10 and wound on a bobbin 11 to obtain a yarn 12 in which the different filaments are blended together. In this case it is possible to use two or more kinds of yarns different in chemical and/or physical properties such as dyeability, hygroscopicity and shrinkability in accordance with the desired object to improve the properties of filament yarn. In this case, in order to assure more effective blending of filaments, it is preferable that the tension applied by the tension means 4 is so adjusted as to make the elongations of both yarns equal to each other. The spreading widths of the respective yarns may be made equal to each other by utilizing the ring-like guides 13 prior to overlapping them together at the rolls 7,7.
The method of this invention is applicable to any kind of multifilament yarn. If desired, the apparatus may be combined with a conventional pneumatic or supersonic wave apparatus known to spread a multifilament yarn into monofilaments. Further according to this invention, since spreading is effected not only by a mere repulsion due to electric charge but also by the mutual action of the first and second electrodes, it can be carried out with a relatively low voltage. Therefore, safety is high. Further, since there is no need of providing water supply means, the apparatus is simple and free from contamination, and as long as the yarn contains only the ordinary textile processing agents including an anti-static agent deposited thereon in the course of spinning operation, there is no need of effecting any special pretreatment such as cleaning or wetting before subjecting the yarn to the spreading treatment of this invention. Moreover, according to this invention, there is no need of specially adjusting the humidity provided that the atmosphere is that of the ordinary textile mill. Further, since yarn spreading does not occur between the first electrode and the feed rollers, there is no danger of the fiber being damaged by being rubbed as the yarn passes through the narrow passage of the first electrode.
The following examples illustrate the invention.
EXAMPLE 1
A nylon multifilament yarn (70 deniers, 24 monofilaments) having a twist of two turns per meter was passed through an apparatus as shown in FIG. 1 in an atmosphere of a relative humidity of 70 percent, under a tension of 0.01 gram/denier and at a speed of 700 meters per minute. In the apparatus, the first electrode 5 was 5 mm. in length and formed with a narrow passage of an inner diameter of 0.7 mm. The frustoconical second electrode 6 had a height of 10 mm., top diameter 6 mm. and bottom diameter of 10 mm. The lower end of the first electrode was arranged to lie on the top surface of the second electrode. The voltage of the first electrode was 4,000 volts, while the second electrode was grounded. The rolls 7 were placed at a distance of 30 cm. from the bottom of the second electrode. The spread monofilaments were flattened at the rolls 7 at which the maximum spreading width was 47 mm.
EXAMPLE 2
A non-twisted viscose rayon multifilament yarn (60 deniers, 20 multifilaments) was passed through an apparatus as shown in FIG. 1 in an atmosphere of a relative humidity of 70 percent and at a speed of 100 meters per minute (overfeed at the feed rollers 3 was 0.5 percent). In the apparatus, the first electrode 5 was 10 mm. in length and had a passage of an inner diameter of 0.7 mm. The frustoconical second electrode 6 had a height of 10 mm., top diameter of 6 mm. and bottom diameter of 12 mm. The distance between the lower end of the first electrode and top surface of the second electrode was 1 mm. The spread monofilaments were flattened at the rolls 7 at which the maximum spreading width was 53 mm. The rolls 7 were placed at a distance of 40 cm. from the bottom of the second electrode.