EP4311869A1

EP4311869A1 - Method of manufacturing thick and thin yarn

Info

Publication number: EP4311869A1
Application number: EP23183282.5A
Authority: EP
Inventors: Yoshimitsu Demizu
Original assignee: TMT Machinery Inc
Current assignee: TMT Machinery Inc
Priority date: 2022-07-27
Filing date: 2023-07-04
Publication date: 2024-01-31
Also published as: CN117468144A; JP2024018984A; TW202405270A

Abstract

An object of the present invention is to manufacture a thick and thin yarn by a simple method.

In a method of manufacturing the thick and thin yarn, a false-twisted processed yarn Yf formed by false-twisting a raw yarn Yr formed of polyester synthetic fibers is made uneven in terms of dyeability. In this manufacturing method, the false-twisted processed yarn Yf is sent to the downstream side in a yarn running direction by a third feed roller 18 and a fourth feed roller 20 and heated by a second heater 19 including a contact surface 56. A heating temperature of the second heater 19 is set so that the false-twisted processed yarn Yf is at least partially heated to a predetermined temperature or more in the second heater 19. At the predetermined temperature, the dyeability of the false-twisted processed yarn Yf varies and the false-twisted processed yarn Yf is thermally contracted. An overfeed rate is maintained at 15 % or more. With this arrangement, the false-twisted processed yarn Yf which runs while being thermally contracted is relaxed and sent to the downstream side in the yarn running direction.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a method of manufacturing a thick and thin yarn.
Patent Literature 1 ( Japanese Unexamined Patent Publication No. 2021-183732 ) discloses a method of manufacturing a false-twisted processed yarn which is formed by performing false twisting of a yarn made of polyester synthetic fibers. In this manufacturing method, before the false twisting, a running highly-oriented undrawn yarn makes contact with a hot pin so as to be heated and drawn. This intentionally causes uneven drawing in the running yarn. When (i) fabric is manufactured with the false-twisted processed yarn formed of this yarn and (ii) the fabric is dyed with heated dye, the fabric has the texture of grain (i.e., uneven dyeing occurs in the fabric).

SUMMARY OF THE INVENTION

Hereinafter, when (i) a yarn is longitudinally uneven in terms of dyeability and (ii) the yarn is dyed and used as a material of fabric having the texture of grain, such a yarn is referred to as a thick and thin yarn regardless of the shape, structure, and material of the yarn for the sake of the convenience. Although not shown in Patent Literature 1, when a running yarn (single yarn) is drawn while being in contact with the above-described hot pin, a thick and thin yarn is manufactured as described below. A known stick-slip phenomenon is intentionally caused in such a way that the running speed and tension of the yarn and the friction force occurred between the yarn and the hot pin are adjusted to meet specific conditions. Because of this, the running speed of the yarn in contact with the hot pin is intentionally changed over time. As a result, in a longitudinal direction of the yarn, a microcrystal part (thin part) which is significantly drawn and which is oriented in the longitudinal direction and an amorphous part (thick part) which is not drawn as significant as the microcrystal part and in which the amorphous state is remained are alternately formed at the yarn. The dye is unlikely to permeate the microcrystal part, and likely to permeate the amorphous part.
When the thick and thin yarn is manufactured by means of the hot pin, the running speed of the yarn cannot be increased. This is in order to avoid the breakage of the yarn due to friction with the hot pin.
An object of the present invention is to rapidly manufacture a thick and thin yarn.
According to a first aspect of the invention, a method of manufacturing a thick and thin yarn is a method of manufacturing the thick and thin yarn which is a yarn made uneven in terms of the dyeability in a longitudinal direction of the yarn. The yarn is a false-twisted processed yarn formed by false-twisting a raw yarn formed of polyester synthetic fibers. The manufacturing method includes: a step of sending the false-twisted processed yarn to a downstream side in a yarn running direction in which the false-twisted processed yarn runs by means of a first yarn supplying device configured to send the false-twisted processed yarn to the downstream side in the yarn running direction and a second yarn supplying device provided downstream of the first yarn supplying device in the yarn running direction and heating the false-twisted processed yarn by means of a heater provided between the first yarn supplying device and the second yarn supplying device in the yarn running direction, the heater including a heat source and a contact surface which is formed at a heating unit heated by the heat source, which extends along the yarn running direction, and which is provided to be in contact with the false-twisted processed yarn; a step of setting a heating temperature of the heater so that the false-twisted processed yarn is at least partially heated to a predetermined temperature or more in the heater, the dyeability of the false-twisted processed yarn varying and the false-twisted processed yarn being thermally contracted at the predetermined temperature; and a step of relaxing and sending the false-twisted processed yarn, which runs while being thermally contracted, to the downstream side in the yarn running direction by maintaining an overfeed rate calculated based on a first yarn feeding speed of the first yarn supplying device and a second yarn feeding speed of the second yarn supplying device at 15 % or more, the second yarn feeding speed being lower than the first yarn feeding speed.
In this regard, synthetic fibers made of a material made from polyalcohol and polyvalent carboxylic acid which are subjected to dehydration synthesis are generally called the polyester synthetic fibers. The thick and thin yarn of the present invention is the yarn which is uneven in terms of the dyeability in the longitudinal direction and which is used as a material of fabric having the texture of grain. The dyeability is the easiness of being dyed with dye. According to the present invention, when the false-twisted processed yarn which is the yarn having been false-twisted is heated to the predetermined temperature or more, the dyeability of the false-twisted processed yarn varies. Furthermore, the false-twisted processed yarn is caused to run while being thermally contracted. The inventors of the subject application have found that the thick and thin yarn is manufactured by sending the false-twisted processed yarn at a high overfeed rate of 15 % or more while relaxing the false-twisted processed yarn. The present inventors have considered the reason of this as follows. While being significantly relaxed, the running false-twisted processed yarn is slightly waved so as to have, in the longitudinal direction, parts which are in contact with the contact surface and reliably heated and parts which are not in contact with the contact surface and not reliably heated. In the false-twisted processed yarn, each part in close contact with the contact surface is heated to a high temperature so as to be thermally contracted and to be increased in thickness. This allows this thick part (hereinafter, this part will be referred to as a first yarn part) to further easily make contact with the contact surface. As a result, the temperature of the false-twisted processed yarn is increased to the predetermined temperature or more so that thermal contraction (and varying of the dyeability) progresses from each first yarn part in the longitudinal direction. Meanwhile, in the false-twisted processed yarn, each part in less contact with the contact surface as compared to the first yarn part (hereinafter, this part will be referred to as a second yarn part) is unlikely to be heated to a high temperature. Therefore, the progress of the thermal contraction is suppressed at each second yarn part as compared to the first yarn part. Because of this, the second yarn part is unlikely to be increased in thickness, and the thermal contraction (and the varying of the dyeability) is further suppressed at the second yarn part as compared to the first yarn part. With this arrangement, a part whose dyeability significantly varies and a part whose dyeability less significantly varies in the longitudinal direction are alternately formed at the false-twisted processed yarn. As described above, the manufacturing method in the present invention does not need a hot pin. This avoids a concern about yarn breakage described above, and thus the yarn is caused to rapidly run. As described above, the yarn is caused to run at the high overfeed rate of 15 % or more. It is therefore possible to rapidly manufacture the thick and thin yarn.
According to a second aspect of the invention, the method of manufacturing the thick and thin yarn of the first aspect is arranged such that the false-twisted processed yarn is formed of a single yarn.
A known method of manufacturing the thick and thin yarn is typically a method including a step of false-twisting and combining two yarns having different thermal shrinkages. However, this method requires (i) a large facility for the false twisting and combining of the two yarns and (ii) raw yarns of two types with different characteristics. According to this aspect, the thick and thin yarn is manufactured only by heating the one false-twisted processed yarn while relaxing the false-twisted processed yarn. It is therefore possible to manufacture the thick and thin yarn with a simple structure and method.
According to a third aspect of the invention, the method of manufacturing the thick and thin yarn of the second aspect is arranged such that each of the first yarn feeding speed and the second yarn feeding speed is not less than 600 m/min.
According to this aspect, the thick and thin yarn is rapidly manufactured.
According to a fourth aspect of the invention, the method of manufacturing the thick and thin yarn of any one of the first to third aspects is arranged such that, when a material of the false-twisted processed yarn is heated to the predetermined temperature or more, the crystal state of the material of the false-twisted processed yarn changes so that the dyeability of the material of the false-twisted processed yarn varies.
The material of polyester synthetic fibers is typically a material whose dyeability varies in accordance with its crystal state. According to this aspect, the dyeability of the false-twisted processed yarn is intentionally made uneven in the longitudinal direction by simply causing the false-twisted processed yarn to run at a predetermined overfeed rate while heating the false-twisted processed yarn.
According to a fifth aspect of the invention, the method of manufacturing the thick and thin yarn of the fourth aspect is arranged such that the predetermined temperature is a melting point of the material of the false-twisted processed yarn.
When the false-twisted processed yarn is heated to the melting point of the material of the false-twisted processed yarn or more, the crystal state of this material is significantly varied.
According to a sixth aspect of the invention, the method of manufacturing the thick and thin yarn of the fifth aspect is arranged such that the melting point is not less than 255 degrees centigrade.
The melting point of the polyester synthetic-fiber material is typically within the approximate range of 255 to 260 degrees centigrade. Alternatively, the melting point of this material may be higher than 260 degrees centigrade. According to this aspect, when the false-twisted processed yarn is heated to such a high temperature, the crystal state of this material is significantly varied.
According to a seventh aspect of the invention, the method of manufacturing the thick and thin yarn of the sixth aspect is arranged such that a setting value of a temperature of the heating unit is not less than 350 degrees centigrade in the heater.
According to this aspect, the false-twisted processed yarn is effectively heated because the setting value of the temperature of the heating unit is high, i.e., not less than 350 degrees centigrade. With this arrangement, even when the running speed of the false-twisted processed yarn is high, the false-twisted processed yarn is heated to a desired temperature. It is therefore possible to rapidly manufacture the thick and thin yarn.
According to an eighth aspect of the invention, the method of manufacturing the thick and thin yarn of the seventh aspect is arranged such that the setting value of the temperature of the heating unit is not less than 400 degrees centigrade in the heater.
According to this aspect, the false-twisted processed yarn is effectively heated because the setting value of the temperature of the heating unit is high, i.e., not less than 400 degrees centigrade. With this arrangement, even when the running speed of the false-twisted processed yarn is high or when the false-twisted processed yarn is thick and difficultly heated, the false-twisted processed yarn is heated to a desired temperature. It is therefore possible to rapidly manufacture the thick and thin yarn.
According to a ninth aspect of the invention, the method of manufacturing the thick and thin yarn of the seventh or eighth aspect is arranged such that the thickness of the false-twisted processed yarn is not less than 50 dtex.
According to this aspect, the false-twisted processed yarn can be efficiently heated. Therefore, the present invention of this aspect makes it possible to manufacture the thick and thin yarn with stable quality even when the false-twisted processed yarn which is thick and difficultly heated is used.
According to a tenth aspect of the invention, the method of manufacturing the thick and thin yarn of any one of the first to ninth aspects is arranged such that, while the raw yarn provided upstream of the first yarn supplying device in the yarn running direction is false-twisted so as to form the false-twisted processed yarn, the false-twisted processed yarn is caused to run toward the first yarn supplying device.
According to this aspect, while being formed, the false-twisted processed yarn is used for manufacturing the thick and thin yarn. In the method of manufacturing this aspect, it is especially effective to rapidly manufacture the thick and thin yarn.
According to an eleventh aspect of the invention, the method of manufacturing the thick and thin yarn of any one of the first to tenth aspects is arranged such that a yarn path of the false-twisted processed yarn is set in advance so that the false-twisted processed yarn makes contact with the contact surface on an assumption that the false-twisted processed yarn runs in the heater without being relaxed.
In one method, the false-twisted processed yarn is caused to make contact with the contact surface only when this yarn runs while being relaxed. In this method, the yarn path of the false-twisted processed yarn which runs in the heater without being relaxed needs to be separated from the contact surface. It is therefore very difficult to set an appropriate yarn path in this method. According to this aspect, the yarn path is just set so that, when being not relaxed, the false-twisted processed yarn makes contact with the contact surface. It is therefore possible to easily set the appropriate yarn path.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a profile of a yarn processor configured to embody a method of manufacturing thick and thin yarns in the present embodiment.
FIG. 2 is a schematic diagram of the yarn processor, expanded along paths of yarns.
Each of FIG. 3(a) to 3(c) shows a second heater.
FIG. 4 is a photograph of fabric manufactured with the yarns manufactured by the yarn processor.
FIG. 5 is a photograph of fabric manufactured with the thick and thin yarns.
FIG. 6 is a drawing prepared for explaining a mechanism of forming a thick and thin yarn.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following will describe an embodiment of the present invention. A vertical direction to the sheet of FIG. 1 is defined as a base longitudinal direction, and a left-right direction to the sheet is defined as a base width direction. A direction orthogonal to the base longitudinal direction and the base width direction is defined as an up-down direction (i.e., vertical direction) in which the gravity acts. In this regard, the base longitudinal direction and the base width direction are substantially in parallel to the horizontal direction.

(Overall Structure of Yarn Processor)

To begin with, the following will describe the overall structure of a yarn processor 1 configured to embody a method of manufacturing thick and thin yarns in the present embodiment, with reference to FIG. 1 and FIG. 2. FIG. 1 is a profile of the yarn processor 1. FIG. 2 is a schematic diagram of the yarn processor 1, expanded along paths of yarns Y (i.e., yarn paths). A direction in which the yarns Y run will be referred to as a yarn running direction.
The yarn processor 1 is configured to process yarns Y made of synthetic fibers (e.g., polyester synthetic fibers). In the present embodiment, processing includes manufacturing (i.e., false twisting) of false-twisted processed yarns. Each yarn Y is, e.g., a multi-filament yarn made of plural filaments. Alternatively, each yarn Y may be made of one filament. The yarn processor 1 includes a yarn supplying unit 2, a processing unit 3, and a winding unit 4. The yarn supplying unit 2 is able to supply the yarns Y. The processing unit 3 is configured to take the yarns Y out from the yarn supplying unit 2 and to process the yarns Y. The winding unit 4 is configured to wind the yarns Y processed by the processing unit 3 onto winding bobbins Bw. Components of the yarn supplying unit 2, the processing unit 3, and the winding unit 4 are aligned to form plural lines (see FIG. 2) in the base longitudinal direction. The base longitudinal direction is a direction orthogonal to a running plane (plane of FIG. 1) of the yarns Y. The running plane of the yarns Y is formed of the yarn paths extending from the yarn supplying unit 2 to the winding unit 4 via the processing unit 3.
The yarn supplying unit 2 includes a creel stand 7 retaining yarn supply packages Ps, and is configured to supply the yarns Y to the processing unit 3. The processing unit 3 is configured to take the yarns Y (raw yarns Yr) out from the yarn supplying unit 2 and to process the yarns Y. Each raw yarn Yr is a single yarn (i.e., one multi-filament yarn or one mono-filament yarn). In the processing unit 3, for example, the following components are provided in this order from the upstream side in the yarn running direction: each first feed roller 11; each twist-stopping guide 12; each first heater 13; each cooler 14; each false-twisting device 15; each second feed roller 16; each interlacing device 17; each third feed roller 18 (a first yarn supplying device of the present invention); each second heater 19 (a heater of the present invention); and each fourth feed roller 20 (a second yarn supplying device of the present invention). The winding unit 4 includes plural winding devices 21. Each winding device 21 is configured wind a yarn Y false-twisted by the processing unit 3 onto a winding bobbin Bw, so as to form a wound package Pw.
The yarn processor 1 includes a main base 8 and a winding base 9 that are spaced apart from each other in the base width direction. The main base 8 and the winding base 9 are substantially identical in length in the base longitudinal direction. The main base 8 and the winding base 9 are provided to face each other in the base width direction. The yarn processor 1 includes units termed spans each of which includes a pair of the main base 8 and the winding base 9. In one span, each device is placed so that the yarns Y running while being aligned in the base longitudinal direction can be subjected to the false twisting at the same time. In the yarn processor 1, these spans are placed in a left-right symmetrical manner to the sheet, with a center line C of the base width direction of the main base 8 being set as a symmetry axis (i.e., main base 8 is shared between the left span and the right span). The spans are aligned in the base longitudinal direction.

(Processing Unit)

The following will describe the structure of the processing unit 3 with reference to FIG. 1 and FIG. 2. Each first feed roller 11 is configured to unwind a yarn Y from a yarn supply package Ps attached to the yarn supplying unit 2, and to feed the yarn Y to a corresponding first heater 13. As shown in FIG. 2, for example, the first feed roller 11 is configured to feed one yarn Y to the first heater 13. Alternatively, the first feed roller 11 may be able to feed adjacent yarns Y to the downstream side in the yarn running direction. Each twist-stopping guide 12 is provided to prevent twist of the yarn Y formed by a false-twisting device 15 from being propagated to the upstream side of the twist-stopping guide 12 in the yarn running direction.
Each first heater 13 is configured to heat the yarn Y sent from the first feed roller 11 to a predetermined processing temperature. For example, the first heater 13 is a contactless heater described in Japanese Laid-Open Patent Publication No. 2002-146640 . As shown in FIG. 2, for example, the first heater 13 is able to heat one yarn Y. The first heater 13 may be able to simultaneously heat plural yarns Y. The heating temperature of the first heater 13 (i.e., a set temperature of an unillustrated heat source) is increasable to a high temperature of approximately 550 degrees centigrade. Each cooler 14 is configured to cool the yarn Y heated at the first heater 13. As shown in FIG. 2, for example, the cooler 14 is configured to cool one yarn Y. Alternatively, the cooler 14 may be able to simultaneously cool plural yarns Y.
Each false-twisting device 15 is provided downstream of the cooler 14 in the yarn running direction, and configured to twist the yarn Y. For example, the false-twisting device 15 is a so-called disc-friction false-twisting device. However, the disclosure is not limited to this. Each second feed roller 16 is configured to feed the yarn Y processed by the false-twisting device 15 to a corresponding interlacing device 17. The conveyance speed of conveying the yarn Y by the second feed roller 16 is higher than the conveyance speed of conveying the yarn Y by the first feed roller 11. The yarn Y is therefore drawn and false-twisted between the first feed roller 11 and the second feed roller 16. Each interlacing device 17 is configured to interlace the yarn Y. The interlacing device 17 has, e.g., a known interlace nozzle configured to interlace the yarn Y by means of an airflow.
Each third feed roller 18 is configured to feed, to a corresponding second heater 19, the yarn Y running downstream of the interlacing device 17 in the yarn running direction. As shown in FIG. 2, for example, the third feed roller 18 is configured to feed one yarn Y to the second heater 19. Alternatively, the third feed roller 18 may be able to feed adjacent yarns Y to the downstream side in the yarn running direction. The conveyance speed of conveying the yarn Y by the third feed roller 18 is lower than the conveyance speed of conveying the yarn Y by the second feed roller 16. The yarn Y is therefore relaxed between the second feed roller 16 and the third feed roller 18. To be more specific, the conveyance speed of conveying the yarn Y by the third feed roller 18 is lower than the conveyance speed of conveying the yarn Y by the second feed roller 16 by, e.g., approximately 2.5 to 5 %. However, a difference between these conveyance speeds is not limited to this.
The second heater 19 is configured to heat a yarn Y sent from each third feed roller 18. The second heater 19 extends along, e.g., the vertical direction. The second heater 19 will be detailed later.
Each fourth feed roller 20 is configured to feed the yarn Y heated by the second heater 19 to a corresponding winding device 21. As shown in FIG. 2, for example, the fourth feed roller 20 is able to feed one yarn Y to the winding device 21. Alternatively, the fourth feed roller 20 may be able to feed adjacent yarns Y to the downstream side in the yarn running direction. The conveyance speed of conveying the yarn Y by the fourth feed roller 20 is lower than the conveyance speed of conveying the yarn Y by the third feed roller 18. The yarn Y is therefore relaxed between the third feed roller 18 and the fourth feed roller 20.
The processing unit 3 arranged as described above makes it possible to perform the false twisting as follows, for example. Each yarn Y drawn between the first feed roller 11 and the second feed roller 16 is twisted by the false-twisting device 15. The twist formed by the false-twisting device 15 propagates to the twist-stopping guide 12, but does not propagate to the upstream side of the twist-stopping guide 12 in the yarn running direction. The yarn Y which is twisted and drawn is heated at the first heater 13 and thermally set. After that, the yarn Y is cooled at the cooler 14. The yarn Y is untwisted on the downstream side of the false-twisting device 15 in the yarn running direction. However, the yarn Y is maintained to be wavy in shape on account of the thermal setting described above (i.e., the crimp contraction of the yarn Y is maintained). The false-twisted yarn Y is interlaced by the interlacing device 17 while being relaxed between the second feed roller 16 and the third feed roller 18. After that, the yarn Y is guided toward the downstream side in the yarn running direction. The yarn Y is processed and false-twisted as such, and a false-twisted processed yarn Yf (see FIG. 1) is formed.
The false-twisted processed yarn Yf is then thermally treated by the second heater 19 while being relaxed between the third feed roller 18 and the fourth feed roller 20. Finally, the false-twisted processed yarn Yf sent from the fourth feed roller 20 is wound by the winding device 21.
Traditionally, the thermal treatment performed by the second heater 19 is performed mainly for removing residual torque in the false-twisted processed yarn Yf. When (i) the false-twisted processed yarn Yf is not thermally set by the second heater 19 yet and (ii) the residual torque in the false-twisted processed yarn Yf is relatively large, such a yarn Yf is referred to as a before-thermal-setting false-twisted processed yarn Yh for the sake of convenience.

(Winding Unit)

The following will describe the structure of the winding unit 4 with reference to FIG. 2. The winding unit 4 includes the winding devices 21. Each winding device 21 is able to wind a yarn Y onto one winding bobbin Bw. The winding device 21 includes a fulcrum guide 41, a traverse device 42, and a cradle 43. The fulcrum guide 41 is a guide functioning as a fulcrum when the yarn Y is traversed. The traverse device 42 is able to traverse the yarn Y by means of a traverse guide 45. The cradle 43 is configured to rotatably support the winding bobbin Bw. A contact roller 46 is provided in the vicinity of the cradle 43. The contact roller 46 is configured to apply a contact pressure to a surface of one wound package Pw by making contact therewith. The winding unit 4 arranged as described above makes it possible to wind the yarn Y sent from the fourth feed roller 20 onto the winding bobbin Bw by means of the winding device 21, so as to form the wound package Pw.

(Second Heater)

The following will detail each second heater 19 with reference to FIG. 1 and FIGs. 3(a) to 3(c). FIG. 3(a) is a cross section of a later-described contact heater 19C, which is taken along a direction orthogonal to the vertical direction. FIG. 3(b) is a cross section taken along a line Ab-Ab in FIG. 3(a). FIG. 3(c) is a cross section taken along a line Ac-Ac in FIG. 3(a). As described above, a direction in which the second heater 19 extends (hereinafter, this direction will be referred to as the extending direction) is substantially parallel to the vertical direction. In each of FIGs. 3(b) and 3(c), the upper side of the sheet is defined as one side in the extending direction, and the lower side of the sheet is defined as the other side in the extending direction. In this regard, one side in the extending direction corresponds to, e.g., the upstream side in the yarn running direction. Meanwhile, the other side in the extending direction corresponds to, e.g., the downstream side in the yarn running direction. A direction orthogonal to both the base longitudinal direction and the extending direction is defined as a height direction (see FIG. 3(a)). In FIG. 3(a), the left side of the sheet is defined as one side in the height direction, and the right side of the sheet is defined as the other side in the height direction (the same applies to the FIGs. 3(b) and 3(b): although not illustrated in these figures).
For example, the second heater 19 includes a contactless heater 19N and the contact heater 19C (see FIG. 1). The contactless heater 19N is the same as the above-described first heater 13. The contact heater 19C is configured to efficiently heat a running yarn Y by causing the yarn Y to make contact with a later-described contact surface 56.
In the present embodiment, the contact heater 19C is able to heat, e.g., two yarns Y (yarn Ya and Yb; see FIGs. 3(a) to 3(c)). The length of the contact heater 19C in the extending direction is preferably not less than 0.4 meters and not more than 1.6 meters. Alternatively, the length of the contact heater 19C in the extending direction may be, e.g., not less than 1.0 meters and not more than 1.5 meters. The contact heater 19C with an appropriate length in the extending direction is preferably selected in accordance with conditions such as the type, thickness, and running speed of yarns. The contact heater 19C includes a heat source 51 and a heating unit 52. The contact heater 19C is configured to simultaneously heat the yarns Ya and Yb by causing the running yarns Ya and Yb to make contact with the heating unit 52 heated by the heat source 51.
The heat source 51 is, e.g., a known sheathed heater (electric heater). The sheathed heater includes a heating wire (such as a coil) and a pipe surrounding the heating wire. The sheathed heater is configured to generate Joule heat when an electrical current flows in the heating wire. The heat source 51 extends along the extending direction (see FIG. 3(b)). The heat source 51 is electrically connected to a controller 100 (see FIG. 3(b)) configured to control the heating temperature of the contact heater 19C. The controller 100 is able to set the heating temperature of the contact heater 19C. The controller 100 is configured to control the contact heater 19C based on a value of the set temperature of the contact heater 19C. For example, the controller 100 may be configured to control the contact heater 19C in consideration of (i) the set temperature of the contact heater 19C and (ii) a detection result by a temperature sensor (not illustrated) configured to detect an actual temperature of the heating unit 52. The controller 100 may be electrically connected to other devices forming the yarn processor 1, in addition to the contact heater 19C.
The heating unit 52 is configured to be heated by heat generated by the heat source 51. The heating unit 52 extends in the extending direction along the heat source 51 (see FIGs. 3(b) and 3(c)). In the extending direction, the heating unit 52 and the contact heater 19C are substantially identical in length. For example, when the length of the contact heater 19C in the extending direction is 1.0 meters, the length of the heating unit 52 in the extending direction is also 1.0 meters. The heating unit 52 includes, e.g., two heating members 53 (i.e., heating members 53a and 53b) and two contacted blocks 54 (i.e., contacted blocks 54a and 54b). The heating member 53a and the contacted block 54a are members for heating the yarn Ya. The heating member 53b and the contacted block 54b are members for heating the yarn Yb. The members for heating the yarn Ya oppose the members for heating the yarn Yb over the heat source 51 in, e.g., the base longitudinal direction.
The following will describe the members for heating the yarn Ya. The heating member 53a is made of a metal material such as yellow copper whose specific heat is high. The heating member 53a extends in the extending direction along the heat source 51. The heating member 53a is provided to be in contact with the heat source 51. For example, the heating member 53a is provided on one side of the heat source 51 in the base longitudinal direction (i.e., on the lower side in the sheet of FIG. 3(a)). The heating member 53a includes, e.g., one slit 55 (i.e., slit 55a) which extends in the extending direction and which forms a yarn path. The slit 55a is substantially U-shaped in a cross section orthogonal to the extending direction. The slit 55a is open to the other side in the height direction. In the slit 55a, one contacted block 54 (i.e., contacted block 54a) is housed.
The contacted block 54a forms the yarn path for the yarn Ya to run. The contacted block 54a is, e.g., a long member made of SUS. The contacted block 54a extends at least in the extending direction. The contacted block 54a is housed in the slit 55a. The contacted block 54a is fixed to the heating member 53a while being in contact with the heating member 53a. The temperature of the contacted block 54a is increased by the heat transmitted from the heat source 51 via the heating member 53a. The contacted block 54a includes one contact surface 56 (i.e., contact surface 56a) with which a yarn Y (i.e., yarn Ya) is caused to make contact. The contact surface 56a is oriented at least to the other side in the height direction. The contact surface 56a is curved to be, e.g., substantially U-shaped when viewed in the extending direction (see FIG. 3(a)). In addition to that, the contact surface 56a is, e.g., substantially linear in a cross section orthogonal to the base longitudinal direction (see FIG. 3(c)). Alternatively, the contact surface 56a may be substantially U-shaped in the cross section orthogonal to the base longitudinal direction.
The following will describe the member for heating the yarn Yb. For example, the heating member 53b is provided on the other side of the heat source 51 in the base longitudinal direction (on the upper side in the sheet of FIG. 3(a)). The heating member 53b is in contact with the heat source 51. The heating member 53b includes a slit 55b which is identical in shape with the slit 55a. In the slit 55b, a contacted block 54b structured in the same manner as the contacted block 54a is housed. The contacted block 54b includes a contact surface 56b which is identical in shape with the contact surface 56a. The contact surface 56b is oriented at least to the other side in the height direction. The details of the members for heating the yarn Yb will be omitted.
Each second heater 19 and yarn paths in the vicinity of the second heater 19 are arranged as described below. Assume that the yarn Ya runs in the second heater 19 without being relaxed, for example. In this case, a yarn path of the yarn Ya is set in advance so that the yarn Ya makes contact with the contact surface 56a. Similarly, assume that the yarn Yb runs in the second heater 19 without being relaxed. In this case, a yarn path of the yarn Yb is set in advance so that the yarn Yb makes contact with the contact surface 56b.
In the contact heater 19C arranged as described above, the running yarns Y make contact with the contact surfaces 56 so as to be heated (in a contact manner) by the heating unit 52 via the contact surfaces 56. With this arrangement, the yarns Y are heated. In other words, the yarn paths of the yarns Y are arranged so that the yarns Y make contact with the contact surfaces 56. The temperature of the yarns Y is increased to an appropriate processing temperature by properly setting the type, brand (thickness), and running speed of the yarns Y and the heating temperature of the contact heater 19C. In this regard, the heating temperature of the contact heater 19C may not be identical with the processing temperature. That is, the heating temperature of the contact heater 19C may be set to be higher than a target value of the processing temperature.
As described above, it has been known that the thermal setting (i.e., thermal treatment) performed by the contact heater 19C is performed mainly for removing residual torque in each false-twisted processed yarn Yf (i.e., before-thermal-setting false-twisted processed yarn Yh). Such thermal treatment is normally performed by heating the false-twisted processed yarn Yf to approximately 100 to 220 degrees centigrade. Meanwhile, because the contact heater 19C of the present embodiment includes the above-described heat source 51, the heating temperature of the contact heater 19C can be set as high as the heating temperature of the contactless heater 19N. With this arrangement, the temperature of the contact surfaces 56 of the contact heater 19C is increasable to as high as those heating temperatures. Because of this, the temperature of each false-twisted processed yarn Yf running while being in contact with a contact surface 56 is increasable to a very high temperature which is outside the above-described approximate range of 100 to 220 degrees centigrade. A phenomenon occurring when each false-twisted processed yarn Yf was heated to a high temperature was not known.
There is a known yarn (not illustrated) which is longitudinally uneven in terms of dyeability and which is dyed and used as a material of fabric having the texture of grain. Such a yarn is referred to as a thick and thin yarn regardless of the shape, structure, and material of the yarn for the sake of the convenience. When a running yarn (single yarn) is drawn while being in contact with the hot pin described above, a known stick-slip phenomenon is intentionally caused. Because of this, the running speed of the yarn in contact with the hot pin is intentionally changed over time. As a result, in a longitudinal direction of the yarn, a microcrystal part (thin part) which is significantly drawn and which is oriented in the longitudinal direction and an amorphous part (thick part) which is not drawn as significant as the microcrystal part and in which the amorphous state is remained are alternately formed at the yarn. In this regard, dye is unlikely to permeate the microcrystal part and likely to permeate the amorphous part. The running speed of the yarn cannot be increased when the thick and thin yarn is manufactured by means of the hot pin. This is in order to avoid the breakage of the yarn due to friction with the hot pin.
The inventors of the subject application found a brand new method of rapidly manufacturing the thick and thin yarn as follows, through a lot of experiments with a machine structured in the same manner as the yarn processor 1.

(Method of manufacturing Thick and Thin Yarn)

The following will describe a method of manufacturing each thick and thin yarn in the present embodiment. For the sake of convenience, processing of each before-thermal-setting false-twisted processed yarn Yh into a thick and thin yarn Yt (see FIG. 1) by means of the above-described yarn processor 1 is referred to as a thick and thin process. The before-thermal-setting false-twisted processed yarn Yh has the large residual torque as compared to the before-thermal-setting false-twisted processed yarn Yh having been subjected to this process. However, each before-thermal-setting false-twisted processed yarn Yh is formed by false-twisting a raw yarn Yr. Therefore, the before-thermal-setting false-twisted processed yarn Yh is equivalent to a false-twisted processed yarn of the present invention. Hereinafter, the before-thermal-setting false-twisted processed yarn Yh is simply referred to as a false-twisted processed yarn Yf.
As shown in FIG. 2, the above-described processing unit 3 includes a false-twisting section 3A configured to perform the false twisting and a thick and thin processing section 3B configured to perform the thick and thin process. The false-twisting section 3A is provided downstream of the yarn supplying unit 2 and upstream of the thick and thin processing section 3B in the yarn running direction. The thick and thin processing section 3B is provided downstream of the false-twisting section 3A and upstream of the winding unit 4 in the yarn running direction. The false-twisting section 3A includes each first feed roller 11 to each interlacing device 17 among the components of the processing unit 3. The thick and thin processing section 3B includes each third feed roller 18 to each fourth feed roller 20 among the components of the processing unit 3. In the yarn processor 1 of the present embodiment, each false-twisted processed yarn Yf is formed by false-twisting a raw yarn Yr by means of the false-twisting section 3A, and the false-twisted processed yarn Yf is subsequently sent to the third feed roller 18 of the thick and thin processing section 3B from the false-twisting section 3A. After that, the false-twisted processed yarn Yf is subjected to the thick and thin process performed by the thick and thin processing section 3B.
The present inventors set the false-twisting section 3A to have standard manufacturing conditions (i.e., conditions of manufacture) of each false-twisted processed yarn Yf as described below. Furthermore, the present inventors also set the thick and thin processing section 3B to have conditions as described below. A single yarn formed of synthetic fibers made of PET, which is a typical polyester material, was used as each raw yarn Yr. The thickness of the raw yarn Yr was set so as to have a thickness of 167 dtex (decitex; 48 filaments) after the false twisting. The running speed of each yarn Y (i.e., the conveyance speed of conveying the yarn Y by the second feed roller 16: the same applies hereinbelow) was set at 800 m/min. The heating temperature of an entrance of the first heater 13 (i.e., the upstream part of the first heater 13 in the yarn running direction) was set at 550 degrees centigrade, and that of an exit of the first heater 13 (i.e., the downstream part of the first heater 13 in the yarn running direction) was set at 450 degrees centigrade. A standard disc-friction false-twisting device was used as the false-twisting device 15. The air pressure of the interlacing device 17 was set at 0.25 MPa.
The present inventors set the conditions of the thick and thin processing section 3B so that a combination of heaters with the following lengths was used as each second heater 19. A contactless heater 19N with a length of 0.3 meters in the extending direction was used. A contact heater 19C with a length of 1.0 meters in the extending direction was used. Each false-twisted processed yarn Yf is preheated by the contactless heater 19N, and heated further by the contact heater 19C.
The present inventors set the conditions of the thick and thin processing section 3B as described below. The present inventors processed and wound false-twisted processed yarns Yf onto winding bobbins Bw under the following conditions, so as to form wound packages Pw. To be more specific, the present inventors changed a setting value of the heating temperature of the second heater 19 within a range of at least 300 to 400 degrees centigrade in units of 50 degrees centigrade. In other words, the conditions of heating temperature of the second heater 19 had at least three conditions, i.e., 300, 350, and 400 degrees centigrade. The wound packages Pw were formed under these conditions. In regard to each of these conditions, the present inventors set a setting value of the heating temperature of the contactless heater 19N to be identical with the heating temperature of the contact heater 19C.
The present inventors set a suitable overfeed rate for each of the above-described three heating temperature conditions (i.e., the above-described three conditions regarding the heating temperature of the second heater 19). The definition of the overfeed rate is described below on the premise that the yarn feeding speed of the third feed roller 18 provided upstream of the second heater 19 in the yarn running direction is higher than that of the fourth feed roller 20 provided downstream of the second heater 19 in the yarn running direction. For example, when the overfeed rate is defined as OF, the yarn feeding speed of the third feed roller 18 (i.e., the first yarn feeding speed) is defined as V1, and the yarn feeding speed of the fourth feed roller 20 (i.e., the second yarn feeding speed) is defined as V2, a value of OF is calculated based on the following formula. In this regard, OF is expressed in units of %.
$OF = 100 \times (V1 - V2) / V1$
Under each heating temperature condition with a suitable overfeed rate, even when each false-twisted processed yarn Yf is heated by the second heater 19 and thermally contracted (i.e., thermal contraction), the false-twisted processed yarn Yf is able to run while being relaxed in the thick and thin processing section 3B. The present inventors set each overfeed rate to adjust the tension in the false-twisted processed yarn Yf to zero while monitoring this tension by means of an unillustrated tension sensor. When the heating temperature of the second heater 19 is 300 degrees centigrade, the overfeed rate is set at 3.8 %. When the heating temperature of the second heater 19 is 350 degrees centigrade, the overfeed rate is set at 7.0 %. When the heating temperature of the second heater 19 is 400 degrees centigrade, the overfeed rate is set at 15 %.
The present inventors manufactured pieces of fabric with three kinds of yarns Y which were processed under the above-described heating temperatures of the second heater 19 and the above-described overfeed rates, and checked whether the uneven dyeing occurred. An explanation will be given with reference to photographs shown in FIG. 4 and FIG. 5. The left-right direction to the sheet of each of the figures is defined by defining a longitude direction and a latitude direction of each of FIG. 4 and FIG. 5. The left-right direction to the sheet of each of FIG. 4 and FIG. 5 is defined as the latitude direction. The up-down direction to the sheet of each of FIG. 4 and FIG. 5 is defined as the longitude direction.
The present inventors shaped the pieces of fabric which were formed of three kinds of the yarns Y, by knitting three kinds of the yarns Y into cylindrical shapes with use of a typical cylindrical-knitting machine (not illustrated). The present inventors dyed the shaped pieces of fabric (see FIG. 4). In this regard, high-temperature dyeing which was a typical method of dyeing polyester synthetic fibers was used as a method of dyeing. The heating temperatures of the second heater 19 at the time of forming three kinds of the yarns Y forming the pieces of fabric are 300, 350, and 400 degrees centigrade in this order from the left side in the sheet of FIG. 4. In FIG. 4, the leftmost piece of fabric did not have the texture of grain (i.e., uneven dyeing) at all. In FIG. 4, the central piece of fabric in the left-right direction had some patterns caused by the uneven dyeing. However, this piece of fabric did not have the apparent texture of grain. The rightmost piece of fabric in FIG. 4, i.e., the piece of fabric in FIG. 5 had the apparent texture of grain. That is, the thick and thin yarn Yt which was uneven in terms of dyeability in the longitudinal direction was formed by processing a false-twisted processed yarn Yf with use of the second heater 19 whose heating temperature was set at 400 degrees centigrade.

(Why Thick and Thin Yarn Was Formed)

The present inventors considered the reasons why the thick and thin yarn Yt which was available as a material of the piece of fabric having the apparent texture of grain was formed by setting processing conditions (i.e., conditions of processing) as described above, as follows. FIG. 6 is a drawing prepared for explaining a mechanism of forming the thick and thin yarn Yt.
To begin with, polyester synthetic fibers have the characteristics of varying dyeability (i.e., easiness of being dyed) due to the change of a crystal state. To be more specific, examples of the crystal state of polyester synthetic fibers include an amorphous state in which crystals are randomly oriented and a microcrystal state in which crystals are partially oriented in a regular manner. In each polyester synthetic fiber, because the force of bonding in molecules is low at a part in the amorphous state, dye is likely to permeate this part as compared to a part in the microcrystal state. In each polyester synthetic fiber, the part in the amorphous state is therefore easily dyed (i.e., has high dyeability) as compared to the part in the microcrystal state.
There are some methods of changing the crystal state of polyester synthetic fibers. For example, when a yarn Y is false-twisted by the false-twisting section 3A, the yarn Y is heated and drawn so that (i) crystals of the yarn Y are oriented in a regular manner and (ii) the crystal state of the yarn Y changes to the microcrystal state. The crystal state of polyester synthetic fibers may change when the polyester synthetic fibers are heated to a predetermined temperature or more. For example, when a false-twisted processed yarn Yf is heated to a melting point or a temperature close to the melting point, crystals are randomly oriented so that the crystal state of the false-twisted processed yarn Yf changes from the microcrystal state to the amorphous state.
Each yarn Y is thermally contracted by being heated to a high temperature. When each false-twisted processed yarn Yf is heated to a predetermined temperature or more, the dyeability of the false-twisted processed yarn Yf varies. Furthermore, the false-twisted processed yarn Yf is caused to run while being thermally contracted. The present inventors have considered that the thick and thin yarn Yt is manufactured under the following principle by sending the false-twisted processed yarn Yf described above at a high overfeed rate while relaxing the false-twisted processed yarn Yf. The high overfeed rate is higher than a predetermined value. That is, while being significantly relaxed, the running false-twisted processed yarn Yf is slightly waved so as to have parts in close contact with a contact surface 56 and parts in less contact with the contact surface 56 in the longitudinal direction. In the false-twisted processed yarn Yf, each part in close contact with the contact surface 56 is heated to a high temperature so as to be thermally contracted and to be increased in thickness (e.g., see a first yarn part Ym shown in FIG. 6). This allows each first yarn part Ym to further easily make contact with the contact surface 56. As a result, the temperature of the false-twisted processed yarn Yf is increased to a predetermined temperature or more so that the thermal contraction (and the varying of dyeability) progresses from each first yarn part Ym in the longitudinal direction of the false-twisted processed yarn Yf. Meanwhile, in the false-twisted processed yarn Yf, each part in less contact with the contact surface 56 as compared to the first yarn part Ym (e.g., see a second yarn part Yn shown in FIG. 6) is unlikely to be heated to a high temperature. Therefore, the progress of the thermal contraction is suppressed at each second yarn part Yn as compared to the first yarn part Ym. Because of this, each second yarn part Yn is unlikely to be increased in thickness, and the thermal contraction (and the varying of dyeability) is further suppressed at each second yarn part Yn as compared to the first yarn part Ym. The first yarn parts Ym and the second yarn parts Yn are alternately provided in the longitudinal direction of the false-twisted processed yarn Yf. With this arrangement, a part whose dyeability significantly varies and a part whose dyeability less significantly varies in the longitudinal direction are alternately formed at the false-twisted processed yarn Yf. The thick and thin yarn Yt is manufactured in this way. The present inventors considered as described above.
The present inventors considered that the thick and thin yarn Yt was able to be manufactured under conditions different from the above-described processing conditions, by setting the thick and thin processing section 3B to have appropriate processing conditions. When being heated to a predetermined temperature or more, each false-twisted processed yarn Yf which is formed by false-twisting a raw yarn Yr formed of polyester synthetic fibers has the characteristics of varying dyeability and thermal contraction. In the thick and thin processing section 3B, the heating temperature of the second heater 19 needs to be set so that the false-twisted processed yarn Yf is at least partially heated to a predetermined temperature or more. Furthermore, the overfeed rate needs to be maintained at a predetermined value or more so that the false-twisted processed yarn Yf and sent to the downstream side in the yarn running direction while being relaxed. In this regard, the false-twisted processed yarn Yf runs while being thermally contracted.
A predetermined temperature is, e.g., a melting point of a material (PET, etc.) of the false-twisted processed yarn Yf. To be more specific, for example, the melting point of PET (of the type of homopolymerization) is not less than 255 degrees centigrade and not more than 260 degrees centigrade. This melting point may be more than 260 degrees centigrade.
When the material of the false-twisted processed yarn Yf is heated to a predetermined temperature or more, the crystal state of this material preferably changes so that the dyeability of this material varies in a similar manner as, e.g., PET.
Specifically, the overfeed rate is preferably not less than 15 %. When the overfeed rate is low, the following problems may occur. For example, the false-twisted processed yarn Yf may not be substantially relaxed because of the thermal contraction and the thick and thin yarn Yt may not be formed. The false-twisted processed yarn Yf may receive excessive tension due to the thermal contraction so as to cause yarn breakage.
A contact surface 56 of each contacted block 54 of the contact heater 19C may be linear in a cross section orthogonal to the base longitudinal direction as shown in FIG. 3(c), but is more preferably curved to be substantially U-shaped in this cross section. This allows each false-twisted processed yarn Yf to easily make contact with the contact surface 56, and thus heating efficiency is further improved. In this cross section, a smaller curvature radius typically corresponds to a larger frictional resistance (i.e., running resistance) applied to the running yarn Y by the contact surface 56. Because of this, the yarn Y on the contact surface 56 may be decelerated because of the running resistance so as to be excessively slacked (i.e., relaxed), or the yarn breakage due to the slack may easily occur. Therefore, when the contact surface 56 is curved in this cross section, prevention of the above-described running resistance from being excessive requires, e.g., to appropriately set the curvature radius and to decrease the friction coefficient of the contact surface 56.
Specifically, the yarn running speed (i.e., running speed of yarns) is preferably not less than 600 m/min in order to rapidly manufacture the thick and thin yarn Yt. The yarn running speed is further preferably not less than 800 m/min.
The second heater 19 preferably includes the contact heater 19C. The contact heater 19C is able to rapidly heat the false-twisted processed yarn Yf to a high temperature. The contactless heater 19N is able to preheat the false-twisted processed yarn Yf. However, the contactless heater 19N may not be provided. That is, the false-twisted processed yarn Yf may be heated only by the contact heater 19C. The length of the contactless heater 19N in the extending direction is not limited to 0.3 meters. The length of the contact heater 19C in the extending direction is not limited to 1.0 meters. The thick and thin yarn Yt is manufactured by appropriately setting the yarn running speed in accordance with the length of the second heater 19 in the extending direction and/or the heating temperature of the second heater 19.
The heating temperature of the contact heater 19C (i.e., a setting value of the temperature of each contacted block 54 of the heating unit 52) is preferably not less than 400 degrees centigrade. However, the disclosure is not limited to this. The heating temperature of the contact heater 19C may be less than 400 degrees centigrade as long as each false-twisted processed yarn Yf is at least partially heated to a predetermined temperature or more. For example, the heating temperature of the contact heater 19C may not be less than 350 degrees centigrade. The present inventors have considered that, for example, when the false-twisted processed yarn Yf is thinner than the above-described thickness of 167 dtex or when the yarn running speed is lower than the above-described speed of 800 m/min, the thick and thin yarn Yt is manufactured even by the contact heater 19C whose heating temperature is 350 degrees centigrade. This is reinforced by the above-described patterns caused by the uneven dyeing in the central piece of fabric (in the case of the contact heater 19C whose heating temperature is 350 degrees centigrade) in the left-right direction of the sheet of FIG. 4.
The thickness of the false-twist processed yarn Yf is preferably not less than 50 dtex. In the present embodiment, the false-twisted processed yarn Yf is efficiently heated by the contact heater 19C. It is therefore possible to manufacture a thick and thin yarn with stable quality even when the thick false-twisted processed yarn Yf is used.
As described above, when the false-twisted processed yarn Yf which is a yarn having been false-twisted is heated to a predetermined temperature or more, the dyeability of the false-twisted processed yarn Yf varies. Furthermore, the false-twisted processed yarn Yf is caused to run while being thermally contracted. The thick and thin yarn Yt is manufactured by sending such a false-twisted processed yarn Yf at a high overfeed rate of 15 % while relaxing the false-twisted processed yarn Yf. By maintaining such a high overfeed rate, the yarn Y is caused to run at high speed. It is therefore possible to rapidly manufacture the thick and thin yarn Yt.
The false-twisted processed yarn Yf is formed of a single yarn. Each thick and thin yarn Yt is manufactured only by heating one false-twisted processed yarn Yf while relaxing the false-twisted processed yarn Yf. It is therefore possible to manufacture the thick and thin yarn Yt with a simple structure and method.
In the present embodiment, the false-twisted processed yarn Yf is sent at a high speed of 600 m/min or more. It is therefore possible to rapidly manufacture the thick and thin yarn Yt.
When being heated to a predetermined temperature or more, the material of the false-twisted processed yarn Yf has the characteristics of varying dyeability due to the change of the crystal state. The material of polyester synthetic fibers is typically a material such as PET whose dyeability varies in accordance with its crystal state. In the present embodiment, the dyeability of the false-twisted processed yarn Yf is intentionally made uneven in the longitudinal direction by simply causing the false-twisted processed yarn Yf to run at a predetermined overfeed rate while heating the false-twisted processed yarn Yf.
When the false-twisted processed yarn Yf is heated to a melting point (e.g., 255 degrees centigrade) of the material of the false-twisted processed yarn Yf or more, the crystal state of this material is significantly varied.
In the present embodiment, the false-twisted processed yarn Yf is effectively heated by the heat transmitted via a contact surface 56 of each contacted block 54. With this arrangement, even when the running speed of the false-twisted processed yarn Yf is high, the false-twisted processed yarn Yf is heated to a desired temperature. It is therefore possible to rapidly manufacture the thick and thin yarn Yt.
The false-twisted processed yarn Yf is effectively heated because a setting value of the temperature of the contacted block 54 of the heating unit 52 is high, i.e., not less than 350 degrees centigrade (may not be less than 400 degrees centigrade). With this arrangement, even when the running speed of the false-twisted processed yarn Yf is high, the false-twisted processed yarn Yf is heated to a desired temperature. It is therefore possible to rapidly manufacture the thick and thin yarn Yt.
In the present embodiment, even when the thick false-twisted processed yarn Yf (e.g., with a thickness of 50 dtex or more) is used, the thick and thin yarn Yt with stable quality is manufactured.
In the present embodiment, while being formed, the false-twisted processed yarn Yf is used for manufacturing the thick and thin yarn Yt. In such a manufacturing method, it is especially effective to rapidly manufacture the thick and thin yarn Yt.
Assume that the false-twisted processed yarn Yf runs in the second heater 19 without being relaxed. In this case, a yarn path of the false-twisted processed yarn Yf is set in advance so that the false-twisted processed yarn Yf makes contact with the contact surface 56 in the present embodiment. With this arrangement, an appropriate yarn path is easily set as compared to a case where the false-twisted processed yarn Yf is caused to make contact with the contact surface 56 only when this yarn Yf runs while being relaxed.
The following will describe modifications of the above-described embodiment. The members identical with those in the embodiment above will be denoted by the same reference numerals and the explanations thereof are not repeated.

(1) In the embodiment above, the overfeed rate is preferably not less than 15 %. However, the disclosure is not limited to this. Each false-twisted processed yarn Yf may be relaxed and sent to the downstream side in the yarn running direction in accordance with the speed of the thermal contraction of the false-twisted processed yarn Yf heated by the second heater 19.
(2) In the embodiment above, the yarn running speed is preferably not less than 600 m/min. However, the disclosure is not limited to this. The yarn running speed may be appropriately set in accordance with the length and/or heating temperature of the second heater 19 in the extending direction.
(3) In the embodiment above, the melting point of the material of the false-twisted processed yarn Yf is within the approximate range of 255 to 260 degrees centigrade. However, the disclosure is not limited to this. In the embodiment above, a predetermined temperature is, e.g., the melting point of the material (PET, etc.) of the false-twisted processed yarn Yf. However, the disclosure is not limited to this. A predetermined temperature (or more) may be suitably changed as long as it is a temperature at which the dyeability of the material of the false-twisted processed yarn Yf varies and the material of the false-twisted processed yarn Yf is thermally contracted.
(4) In the embodiment above, when the material of the false-twisted processed yarn Yf is heated to a predetermined temperature or more, the crystal state of this material changes so that the dyeability of this material varies. However, the disclosure is not limited to this. When being heated to a predetermined temperature or more, the material of the false-twisted processed yarn Yf may have the characteristics of varying dyeability due to a phenomenon which is different from the change of the crystal state.
(5) In the embodiment above, each contacted block 54 is provided as a member including a contact surface 56. However, the disclosure is not limited to this. Instead of the contacted block 54, for example, a SUS plate (not illustrated) formed as sheet metal may be housed in each slit 55 (see Japanese Laid-Open Patent Publication No. 2002-194631 , etc.). The sheet metal is substantially U-shaped when viewed in the extending direction. A contact surface (not illustrated) may be formed on such a SUS plate.
(6) In the embodiment above, a yarn path of the false-twisted processed yarn Yf is provided so that the false-twisted processed yarn Yf makes contact with the contact surface 56 provided at the second heater 19. Assume that the false-twisted processed yarn Yf runs in the second heater 19 without being relaxed. In this case, this yarn path is set in advance so that the false-twisted processed yarn Yf makes contact with the contact surface 56. However, the disclosure is not limited to this. Assume that the false-twisted processed yarn Yf runs in the second heater 19 without being relaxed. In this case, the yarn path of the false-twisted processed yarn Yf may be set so that the false-twisted processed yarn Yf is slightly separated from the contact surface 56 (i.e., the false-twisted processed yarn Yf is adjacent to the contact surface 56). Furthermore, the running false-twisted processed yarn Yf is waved in the second heater 19 so that a part of the false-twisted processed yarn Yf in the longitudinal direction makes contact with the contact surface 56.
(7) In the embodiment above, when the false-twisting section 3A is set to have the above-described standard manufacturing conditions of each false-twisted processed yarn Yf, each thick and thin yarn Yt is manufactured. However, the thick and thin yarn Yt is expected to be manufactured under manufacturing conditions different from the above-described manufacturing conditions, by setting the thick and thin processing section 3B to have appropriate processing conditions.
(8) In the embodiment above, the second heater 19 is able to heat two yarns Y. However, the disclosure is not limited to this. The second heater 19 may be able to heat one yarn Y. Alternatively, the second heater 19 may be able to heat three or more yarns Y.
(9) The structure of the false-twisting section 3A is not limited to the above. For example, each first heater 13 may be a known contact Dowtherm heater. The thick and thin processing section 3B may be applied not only to the yarn processor 1, but also to a yarn processor (not illustrated) which is differently structured. For example, the present invention may be structured so that the thick and thin processing section 3B is provided at a re-winder described in Japanese PCT application entering national phase in Japan No. 2019/225138 .

Claims

A method of manufacturing a thick and thin yarn (Yt) which is a yarn (Y) made uneven in terms of the dyeability in a longitudinal direction of the yarn (Y),
the yarn (Y) being a false-twisted processed yarn (Yf) formed by false-twisting a raw yarn (Yr) formed of polyester synthetic fibers,

the manufacturing method comprising: a step of sending the false-twisted processed yarn (Yf) to a downstream side in a yarn running direction in which the false-twisted processed yarn (Yf) runs by means of a first yarn supplying device (18) configured to send the false-twisted processed yarn (Yf) to the downstream side in the yarn running direction and a second yarn supplying device (20) provided downstream of the first yarn supplying device (18) in the yarn running direction and heating the false-twisted processed yarn (Yf) by means of a heater (19) provided between the first yarn supplying device (18) and the second yarn supplying device (20) in the yarn running direction,

the heater (19) including a heat source (51) and a contact surface (56) which is formed at a heating unit (52) heated by the heat source (51), which extends along the yarn running direction, and which is provided to be in contact with the false-twisted processed yarn (Yf);

a step of setting a heating temperature of the heater (19) so that the false-twisted processed yarn (Yf) is at least partially heated to a predetermined temperature or more in the heater (19), the dyeability of the false-twisted processed yarn (Yf) varying and the false-twisted processed yarn (Yf) being thermally contracted at the predetermined temperature; and

a step of relaxing and sending the false-twisted processed yarn (Yf), which runs while being thermally contracted, to the downstream side in the yarn running direction by maintaining an overfeed rate calculated based on a first yarn feeding speed of the first yarn supplying device (18) and a second yarn feeding speed of the second yarn supplying device (20) at 15 % or more, the second yarn feeding speed being lower than the first yarn feeding speed.
The method of manufacturing the thick and thin yarn (Yt) according to claim 1, wherein, the false-twisted processed yarn (Yf) is formed of a single yarn.
The method of manufacturing the thick and thin yarn (Yt) according to claim 2, wherein, each of the first yarn feeding speed and the second yarn feeding speed is not less than 600 m/min.
The method of manufacturing the thick and thin yarn (Yt) according to any one of claims 1 to 3, wherein, when a material of the false-twisted processed yarn (Yf) is heated to the predetermined temperature or more, the crystal state of the material of the false-twisted processed yarn (Yf) changes so that the dyeability of the material of the false-twisted processed yarn (Yf) varies.
The method of manufacturing the thick and thin yarn (Yt) according to claim 4, wherein, the predetermined temperature is a melting point of the material of the false-twisted processed yarn (Yf).
The method of manufacturing the thick and thin yarn (Yt) according to claim 5, wherein, the melting point is not less than 255 degrees centigrade.
The method of manufacturing the thick and thin yarn (Yt) according to claim 6, wherein, a setting value of a temperature of the heating unit (52) is not less than 350 degrees centigrade in the heater (19).
The method of manufacturing the thick and thin yarn (Yt) according to claim 7, wherein, the setting value of the temperature of the heating unit (52) is not less than 400 degrees centigrade in the heater (19).
The method of manufacturing the thick and thin yarn (Yt) according to claim 7 or 8, wherein, the thickness of the false-twisted processed yarn (Yf) is not less than 50 dtex.
The method of manufacturing the thick and thin yarn (Yt) according to any one of claims 1 to 9, wherein, while the raw yarn (Yr) provided upstream of the first yarn supplying device (18) in the yarn running direction is false-twisted so as to form the false-twisted processed yarn (Yf), the false-twisted processed yarn (Yf) is caused to run toward the first yarn supplying device (18).
The method of manufacturing the thick and thin yarn (Yt) according to any one of claims 1 to 10, wherein, a yarn path of the false-twisted processed yarn (Yf) is set in advance so that the false-twisted processed yarn (Yf) makes contact with the contact surface (56) on an assumption that the false-twisted processed yarn (Yf) runs in the heater (19) without being relaxed.