JP5087267B2 - Flameproofing method for carbon fiber precursor - Google Patents

Description

  The present invention relates to a flameproofing method for a carbon fiber precursor.

Conventionally, in order to continuously and efficiently perform flameproofing treatment and carbonization treatment, a process of connecting a terminal end and a starting end of a plurality of carbon fiber precursors to obtain a continuous single tow is known. Yes. In addition, as a pre-process of the yarn splicing process, a process of making the end portion of the carbon fiber precursor toe flame resistant is known. This flameproofing process at the end prevents the toe joint from causing yarn breakage due to heat storage in the subsequent flameproofing process (see, for example, Patent Document 1).
Japanese Patent No. 3706754

  However, in the conventional flameproofing method for the end of the tow that is the carbon fiber precursor, for example, a yarn such as carbon fiber is joined to the end of the tow, and the lead is pulled into the flameproofing furnace. The end of the tow is introduced and heated to make it flame resistant. At this time, there is a problem that the tow shrinks and twists due to heat and accumulates heat to cause yarn breakage. Such yarn breakage due to the heat storage of the carbon fiber precursor tow can be prevented by lowering the furnace temperature when introducing the tow into the furnace, but if the furnace temperature is lowered, the flame resistance is again reduced. However, there is a problem that it takes a long time for the flameproofing treatment because it is necessary to raise the temperature to such a temperature.

  Therefore, the present invention provides a flameproofing treatment that can stably flameproof the end of the tow in a short time without causing yarn breakage due to heat storage during the flameproofing treatment of the end of the tow that is the carbon fiber precursor. A method is provided.

In order to solve the above-mentioned problems, the present invention provides a tow end and end of the tow before joining the end of the tow that is the carbon fiber precursor and the start of the other tow to obtain a continuous tow. A flameproofing treatment method for flameproofing a part, wherein a tow width per unit fineness of tow is in a range of 2.0 × 10 ⁻³ mm / tex or more and 5.0 × 10 ⁻³ mm / tex or less, The tension per unit fineness of the tow is in the range of 2.0 mN / tex or more and 25.0 mN / tex or less , and a constant tension is applied by fixing the weight to the end of the tow, while the wind speed is 1.0 m / wherein the treating flame the beginning and end of the tow and constant temperature at 2 5 0 ° C. or more with hot air of s or more and 4.0 m / s or less.
By performing the flameproofing treatment in this manner, it is possible to limit the form of the carbon fiber precursor tow and prevent the tow from being excessively stored when the flameproofing furnace is inserted. Moreover, shrinkage | contraction, twist, etc. of a tow | toe are prevented with the provided tension | tensile_strength and excessive heat storage of a tow | toe can be prevented. In addition, it is possible to prevent the tow from being out of tension due to excessive tension during heating. Further, the hot air circulates in the furnace at the above wind speed, so that it is possible to prevent the tow from being appropriately removed from heat and being excessively stored. Further, it is possible to process continuously and efficiently flame-resistant carbon fiber precursor tow by a furnace to a high temperature of more than 2 5 0 ° C..

  According to the present invention, yarn breakage due to excessive heat storage of the carbon fiber precursor and breakage due to excessive tension can be prevented, and the flameproofing treatment can be efficiently performed while maintaining the furnace temperature at a high temperature. Thus, the end portion of the carbon fiber precursor yarn can be flameproofed stably.

Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 and FIG. 2 show, for example, an end portion flameproofing treatment in which a plurality of flameproofing treatments are simultaneously performed on the starting end portions 1a and 2a and the terminating end portions 1b and 2b of tow 1 and 2, which are carbon fiber precursors such as acrylic fibers. Device 100. The flameproofing treatment of the ends 1a, 1b, 2a and 2b of each tow is performed as a pre-process of the yarn splicing process, and prevents the joined portion of the joined single tow from breaking off due to heat accumulation during the flameproofing treatment. And it aims at performing the flame-proofing process and carbonization process of a carbon fiber precursor continuously. Here, the yarn splicing step refers to the end portion of the tow 1 such as the end portion 1b of the tow 1 and the start end portion 2a of another tow 2, the end portion 2b of another tow 2 and the start end portion of another tow. It is a step of repeatedly joining and obtaining a single continuous length of tow capable of continuously producing carbon fibers.

  The end flameproofing apparatus 100 includes an end flameproofing furnace 3 having a rectangular cross section. The high temperature part of the end flameproofing furnace 3 is formed of a structural material such as iron or stainless steel, for example. The end flameproofing furnace 3 includes a tow inlet 4 for drawing tow 1 and 2 which are carbon fiber precursors into the furnace, and a tow for drawing the tows 1 and 2 facing the tow inlet 4 to the outside of the furnace. An outlet 5 is provided. The end flameproofing furnace 3 includes a hot air circulation device (not shown). The hot air circulation device includes a heater, a fan, a temperature detector, a temperature / fan rotation speed control device, and the like, and can arbitrarily set the wind speed and temperature of the hot air circulating in the furnace.

  The end flameproofing furnace 3 is composed of an upper part 7 and a lower part 8, and the upper part 7 and the lower part 8 are connected to each other via hinges 9, 9 provided on the back surface of the end part flameproofing furnace 3, It can be opened and closed in the direction of arrow A. In addition, for safety during opening and closing, a wire (not shown) is provided to limit the amount of opening and closing between the upper portion 7 and the lower portion 8. The end flameproofing furnace 3 is provided with moving means 6 and 6 such as wheels at the bottom, and is movable forward and backward (in the direction of arrow B).

  Tow 1 and 2 which are carbon fiber precursors are supplied in a state where they are folded and stacked in boxes 11 and 12, for example. Rollers 13 and 14 for winding the start end portions 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 accommodated in the box are provided on the upper portions of the boxes 11 and 12 in which the toe 1 and 2 are accommodated. In FIG. 1, the rotation shaft is provided so as to be rotatable substantially perpendicular to the paper surface. A roller 15 is provided in a state where the rollers 13 and 14 provided on the boxes 11 and 12 are spaced apart in the right direction and the rollers 13 and 14 on the box and the rotation axis are substantially parallel to each other.

  On the right side of the roller 15 on both sides of the tows 1 and 2 in the width direction, as shown in FIG. 17 is provided. The toe width regulating plate 16 is provided so as to be slidable on the pedestal 17 in the width direction of the tow. For example, the distance D between the plates can be freely set by being fixed to the pedestal 17 with a fastener such as a bolt. it can.

  A clamp 21 is provided on the right side of the toe width regulating plate 16 so as to sandwich and fix the tows 1 and 2 from the pedestal 17 in the vertical direction. The clamp 21 can be moved up and down by screws or the like and is fixed to the pedestal 17. A guide roller 22 is provided on the right side of the clamp 21 so as to correspond to the position of the toe inlet 4 of the end flameproofing furnace 3 so that the rotation shaft can be rotated substantially perpendicular to the paper surface in FIG. Similarly, a guide roller 23 is provided outside the toe outlet 5 of the end flameproofing furnace 3 so as to correspond to the position of the toe outlet 5.

Next, the operation of this embodiment will be described.
As shown in FIG. 1 and FIG. 2, the start ends 1 a and 2 a and the end portions of tow 1 and 2, which are carbon fiber precursors supplied in a state of being folded and stacked in a plurality of boxes 11 and 12. 1b and 2b are respectively hung on the rollers 13 and 14 on the upper side of the boxes 11 and 12, and are hung on the rollers 15 arranged on the right side of the boxes 11 and 12 from the upper side. Further, the start ends 1a and 2a and the end portions 1b and 2b of each toe are passed between the toe width regulating plates 16 and passed between the clamp 21 and the pedestal 17 that are opened up and down.

At this time, the distance D between the tow width regulating plates 16 is 2.0 × 10 ⁻³ mm / tex in width per unit fineness of tows 1 and 2 according to the fineness of tows 1 and 2 that are carbon fiber precursors. It sets so that it may satisfy the range above and below 5.0 * 10 < ^-3 > mm / tex. This prevents the tows 1 and 2 from becoming unnecessarily thick, and the shape of the cross-sections of the start ends 1a and 2a and the end portions 1b and 2b of the tow 1 and 2, which are carbon fiber precursors to be flameproofed. Can be prescribed.

  After the start end portions 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 are passed between the clamp 21 and the pedestal 17, they are passed between the two guide rollers 22 and 23, and the clamp 21 is closed to close the tow. In a state where 1 and 2 are sandwiched and fixed, the weight 24 is fixed to the ends of the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2, respectively. As a result, the tension F is applied to the tows 1 and 2. At this time, as shown in FIG. 2, the end portion flameproofing furnace 3 is moved to a position shifted to the rear side (upper side in the drawing). Further, the weight 24 fixed to the ends of the start ends 1a, 2a and the end portions 1b, 2b of the tows 1, 2 has a tension per unit fineness of 2.0 mN / tex or more according to the fineness of the tows, and It determines so that it may become the range of 25.0 mN / tex or less. Thereby, the tension per unit fineness loaded on the tows 1 and 2 can be defined.

Next, as shown in FIGS. 1 to 3, the upper part 7 of the end flameproofing furnace 3 is opened upward through hinge parts 9, 9 provided on the back surface, and the toe end parts 1 a, 2 a and the terminal end of each tow The end flameproofing furnace 3 is moved in the direction of arrow B (downward in the drawing) until the parts 1b and 2b are in a predetermined position in the furnace. Then, by closing the upper portion 7, the start end portions 1 a and 2 a and the end portions 1 b and 2 b of each tow are accommodated in the furnace.
The start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 set in the end flameproofing furnace 3 have a wind speed of 1.0 m / s or more and 4.0 m in the furnace by a hot air circulation device. Hot air is circulated so as to be in the range of / s or less, and the furnace is heated in a state where the temperature in the furnace is 230 ° C. or higher. As a result, the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 fixed in the furnace are made flame resistant.

  At this time, by defining the form of the tow 1 and 2 as the carbon fiber precursor when the end portion flameproofing furnace 3 is inserted as described above by the tow width per unit fineness, the tow 1 and 2 are thicker than necessary. It is possible to prevent the tow 1 and 2 from being excessively stored. In addition, by applying the tension F in which the tension per unit fineness is in the above range, the tows 1 and 2 are prevented from contracting and twisting, and excessive heat storage of the tows 1 and 2 can be prevented. At the same time, it is possible to prevent the tows 1 and 2 from being out of tension due to excessive tension F. In addition, by circulating hot air in the furnace within the range of the above-described wind speed, it is possible to prevent the tows 1 and 2 from being appropriately removed and storing excessive heat. Furthermore, by making the inside of the furnace at a high temperature of 230 ° C. or higher, the carbon fiber precursor tows 1 and 2 can be subjected to flame resistance treatment continuously and efficiently.

  Therefore, according to this embodiment, the tow width per unit fineness, the tension per unit fineness applied at the time of heating, the wind speed of the hot air in the furnace, and the minimum temperature in the furnace are heated in the above-mentioned ranges. Therefore, the yarn breakage due to excessive heat storage of the carbon fiber precursor tow and breakage due to excessive tension F can be prevented, and the flameproofing treatment can be efficiently performed while maintaining the furnace temperature at a high temperature. Thus, the start end portions 1a and 2a and the end portions 1b and 2b of the carbon fiber precursor tows 1 and 2 can be flameproofed.

Further, the top 7 of the end flameproofing furnace 3 can be opened and closed and the end flameproofing furnace 3 can be moved back and forth, so that the tows 1 and 2 are inserted from the toe inlet 4 and the toe outlet 5 is inserted. Compared with the case where it pulls out, the setting of the tow | toe 1,2 can be made easy.
In addition, by opening the upper part 7 of the end flameproofing furnace 3 after the flameproofing treatment of the end parts 1a, 1b, 2a and 2b of the tows 1 and 2 and moving the end part flameproofing furnace 3 rearward, , 2 can be easily taken out of the furnace. Moreover, since it is possible to take out the tows 1 and 2 without touching the heated part, the safety of the work can be improved.
Further, since it is not necessary to use a yarn introduction when inserting the end portions 1a, 1b, 2a, 2b of the tows 1, 2 into the furnace, the operation is facilitated, and the ends 1a, 1b, 2a of the tows 1, 2 are facilitated. , 2b can be improved in productivity.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5 with reference to FIGS.
The end flameproofing furnace 3a shown in FIG. 4 is not integrally openable and closable but is provided integrally, and is not provided with a bottom moving means. In addition, a jig 25 for fixing the tows 1 and 2 together with the carbon fiber precursor tows 1 and 2 is inserted into the furnace, and the ends 1a, 1b, 2a and 2b of the tows 1 and 2 are flameproofed. It is. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 4 and 5, the jig 25 for fixing the ends 1a, 1b, 2a and 2b of the tows 1 and 2 inside the end flameproofing furnace 3a includes a jig frame 26 formed in a frame shape. I have. On both the left and right sides of the upper side of the jig frame 26, rectangular plate-like holding plates 27 and 27 are provided corresponding to the shapes of the left and right frames of the jig frame 26. The holding plates 27 and 27 can be fixed to the jig frame 26 with fasteners such as screws, for example. A rail-shaped guide rail 28 is provided below the jig frame 26, and the jig frame 26 is slidable on the guide rail 28 from side to side. In addition, toe width adjustment plates 29 and 29 for adjusting the widths of the tows 1 and 2 are provided on both the left and right sides of the jig frame 26. The toe width adjusting plates 29 and 29 are plate-like, and are formed with notches 30 through which the tows 1 and 2 pass at the upper part, and are fastened by fasteners such as screws so as to intersect the toe 1 and 2 passing directions at substantially right angles. It is fixed to the jig frame 26. Further, the dimension of the notch 30 of the toe width adjusting plate 29 is set so that the toe width defined by the interval D of the toe width regulating plate 16 can be maintained.

Next, the operation of this embodiment will be described.
As shown in FIG. 1, after the first end portions 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 are passed between the tow width regulating plate 16 and the clamp 21 as in the first embodiment, 4 and 5 is passed between the pressing plate 27 of the jig 25 and the jig frame 26. At this time, the tow width defined by the tow width regulating plate 16 in the same manner as in the first embodiment can be maintained and adjusted by the notch portion 30 of the tow width adjusting plate 29.
The start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 are set to a certain length from the right end of the jig 25, that is, the tows 1 and 2 are passed over the guide rollers 22 and 23. After pulling out the length capable of fixing the weight 24, the tension per unit fineness satisfies the range of 2.0 mN / tex or more and 25.0 mN / tex or less according to the fineness of the tows 1 and 2. The tows 1 and 2 are fixed by the pressing plates 27 and 27 on both sides of the jig 25 in a tensioned state.

Further, the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 pulled out from the right end of the jig 25 are placed on the jig frame 26 so as to be folded back. The start ends 1a, 2a and the end portions 1b, 2b of the tows 1, 2 are inserted together with the jig frame 26 from the toe inlet 4a. At this time, the jig frame 26 is slid on the guide rail 28 by fixing the guide rail 28 of the jig 25 in advance according to the insertion position of the jig 25 in the furnace of the end flameproofing furnace 3a. However, the jig frame 26 can be easily inserted into the furnace.
After the jig frame 26 is inserted into the furnace and the ends of the jig frame 26 are exposed from the toe inlet 4a and the toe outlet 5a, the tows 1, 2 folded back to the upper side of the jig frame 26 are taken from the toe outlet 5a. Pull it out of the furnace and wind it around the guide roller 23 from above.

  Next, in a state where the clamp 21 is closed and the tows 1 and 2 are sandwiched and fixed, the weights 24 are fixed to the ends of the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2, respectively. At this time, like the first embodiment, the weight of the weight 24 fixed to the ends of the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 depends on the fineness of the tows 1 and 2, respectively. The tension per unit fineness is determined so as to satisfy the range of 2.0 mN / tex or more and 25.0 mN / tex or less. Thereby, the tension per unit fineness can be defined.

  Then, the pressing plates 27, 27 of the jig 25 are removed, and the unit F is applied with a tension F applied to the start ends 1a, 2a and end portions 1b, 2b of the tows 1, 2 fixed to the jig 25 and made flameproof. The tension per fineness is applied. Next, the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 have a wind speed of 1.0 m / s or more and 4.0 m / s or less by a hot air circulation device in the end flameproofing furnace 3a. The hot air is circulated so that the furnace temperature is 230 ° C. or higher. As a result, the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 fixed in the furnace are made flame resistant.

  At this time, similarly to the first embodiment, the tow width regulating plate 16 and the tow width adjusting plate 29 define the tow 1 and 2 forms of the carbon fiber precursor, so that the tow 1 is inserted when the end portion flameproofing furnace 3a is inserted. , 2 can be prevented from being excessively stored. Further, the tension per unit fineness is regulated within the same range as in the first embodiment, the tension F is applied, and the toe 1 and 2 are fixed between the holding plates 27 and 27 of the jig 25 to end flame resistance. By inserting it into the conversion furnace 3a, the shrinkage and twisting of the tows 1 and 2 can be prevented, and excessive heat storage of the tows 1 and 2 can be prevented. At the same time, it is possible to prevent the tows 1 and 2 from being out of tension due to excessive tension F. Further, by circulating hot air in the same manner as in the first embodiment, it is possible to prevent the tows 1 and 2 from being appropriately removed from heat and excessively storing heat. Furthermore, by setting the inside of the furnace to a high temperature of 230 ° C. or higher, the toe 1 and 2 of the carbon fiber precursor can be subjected to flameproofing treatment continuously and efficiently as in the first embodiment.

Therefore, according to this embodiment, not only the same effect as in the first embodiment is obtained, but also it is not necessary to open and close the end flameproofing furnace 3a. Fabrication of the flameproofing furnace 3a is facilitated.
In addition, after the flameproofing processing of the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 is completed, the tows 1 and 2 are fixed to the jig 25 by the pressing plates 27 and 27 on the jig frame 26. The jig 25 can be taken out of the furnace in the state. Therefore, as in the first embodiment, it is not necessary to use a yarn introduction when inserting and removing the end portions of the tows 1 and 2 into the furnace. , 1b, 2a, 2b can be improved in productivity.

Next, a third embodiment of the present invention will be described with reference to FIG. 6 with reference to FIGS. 1, 2, and 5.
As shown in FIG. 6, a jig 25a according to this embodiment is provided between a fixing portion 31 at the right end and a jig frame 26a instead of a weight 24 for applying a tension F to the tows 1 and 2. Is provided with an elastic portion 32. Since other configurations are the same as those of the second embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.

  A hole 34 into which the shaft 33 of the elastic portion 32 is inserted is provided at the right end of the jig frame 26a, and one end of the shaft 33 is inserted into the hole 34 so as to be freely inserted and removed. An elastic body such as a spring 35 is provided around the shaft 33, and a lower fixing portion 26b for fixing the ends 1a, 1b, 2a, 2b of the tows 1, 2 is fixed to the other end of the shaft 33. Has been. A pressing plate 27 similar to that of the second embodiment is provided on the upper side of the lower fixing portion 26b so as to be fixed to the lower fixing portion 26b with a fastener such as a screw.

Next, the operation of this embodiment will be described.
After fixing the left pressing plate 27 of the jig 25a, the right end pressing plate 27 is fixed in a state where the spring 35 of the elastic portion 32 is compressed, so that the start end portions 1a, 2a of the tows 1, 2 and Tension F can be applied to the terminal portions 1b and 2b by the elastic force of the spring 35. Further, by adjusting the compression amount of the spring 35, the tension per unit fineness of the tows 1 and 2 can be determined so as to satisfy the range of 2.0 mN / tex or more and 25.0 mN / tex or less.

  Further, by limiting the form of the carbon fiber precursor tows 1 and 2 by the tow width regulating plate 16 and the tow width adjusting plate 29 as in the first and second embodiments, the end flameproofing furnace 3a is inserted. It is possible to prevent the tows 1 and 2 from being excessively stored, and by providing the tension F by defining the tension per unit fineness in the same range as in the first and second embodiments, the tow 1 , 2 is limited, and excessive heat storage of the tows 1 and 2 can be prevented. At the same time, it is possible to prevent the tows 1 and 2 from being out of tension due to excessive tension F. Further, by circulating hot air in the furnace in the same manner as in the first and second embodiments, it is possible to prevent the tows 1 and 2 from being appropriately removed from heat and storing heat excessively. Furthermore, by making the inside of the furnace at a high temperature of 230 ° C. or higher, the tow 1 and 2 of the carbon fiber precursor can be continuously flame-resistant similarly to the first and second embodiments. .

  Therefore, according to this embodiment, not only the same effects as those of the first and second embodiments are obtained, but also the weight 24 is fixed to the start end portions 1a and 2a and the end portions 1b and 2b of the tows 1 and 2, respectively. Therefore, the apparatus can be made compact and the end flameproofing process can be facilitated.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 7, the end flameproofing furnace 3b is not a horizontal type, but a toe inlet 4b is formed at a substantially central portion of the upper top plate, and is opposed to the toe inlet 4b at a substantially central portion of the lower bottom plate. This is a vertical end flameproofing furnace 3b in which a toe outlet 5b is formed. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.

  A nip roller 37 is provided on the top of the toe inlet 4b corresponding to the toe inlet 4b. The nip roller 37 is composed of an upper roller 38 and a lower roller 39. The upper roller 38 is provided so as to be movable up and down, and the rotation shaft of the upper roller 38 is connected to a power source such as a motor (not shown) and can freely rotate. It has become.

Next, the operation of this embodiment will be described.
Similarly to the first embodiment, after passing the start end portions 1a, 2a and the end portions 1b, 2b of the tows 1, 2 between the tow width regulating plates 16, the upper roller 38 and the lower roller 39 of the nip roller 37 are used. Then, the upper roller 38 is moved downward to clamp and fix the tows 1 and 2. In this state, the weight 24 is fixed to the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2, and the upper roller 38 of the nip roller 37 is rotated to lower the weight 24 downward. At this time, the weight of the weight 24 is determined in the same manner as in the first embodiment. In addition, a guide wire (not shown) is connected to the weight 24, the guide wire is fixed in a state where it is taken out of the furnace from the toe outlet 5b, and the weight 24 is lowered along the guide wire, so that The shaking of the weight 24 can be prevented.

  When the weight 24 is inserted into the furnace from the toe inlet 4b of the end flameproofing furnace 3b and sent out of the furnace from the toe outlet 5b through the furnace, the upper roller 38 of the nip roller 37 stops rotating and the clamp 21 Is closed and the tows 1 and 2 are clamped and fixed between the clamps 21. In this state, the hot air is applied to the start ends 1a, 2a and the end portions 1b, 2b of the tows 1, 2 so that the wind speed is in the range of 1.0 m / s to 4.0 m / s. It is circulated and made flame resistant by heating in the furnace of the end flame proofing furnace 3b heated to a temperature of 230 ° C. or higher.

  At this time, similarly to the first embodiment, the tow width restriction plate 16 restricts the form of the carbon fiber precursor tows 1 and 2 so that the tows 1 and 2 store excessive heat when the end portion flameproofing furnace 3b is inserted. Can be prevented. In addition, the tension per unit fineness is regulated within the same range as in the first embodiment, and the tension F is applied to prevent the tows 1 and 2 from shrinking and twisting, and the excessive heat storage of the tows 1 and 2 Can be prevented. At the same time, it is possible to prevent the tows 1 and 2 from being out of tension due to excessive tension F. Further, by circulating hot air in the same manner as in the first embodiment, it is possible to prevent the tows 1 and 2 from being appropriately removed from heat and excessively storing heat. Furthermore, by setting the inside of the furnace to a high temperature of 230 ° C. or higher, the toe 1 and 2 of the carbon fiber precursor can be subjected to flameproofing treatment continuously and efficiently as in the first embodiment.

  Therefore, according to this embodiment, not only the same effect as the first embodiment can be obtained, but also the installation area of the end flameproofing furnace 3b can be reduced by using the vertical end flameproofing furnace 3b. can do. Moreover, since the guide rollers 22 and 23 can be omitted by using the vertical furnace, the apparatus can be simplified and the production efficiency can be improved. Also in the vertical furnace, the direction of the hot air circulating in the furnace can be set freely with respect to the tow as in the conventional horizontal furnace.

In addition, after the flameproofing treatment of the tows 1 and 2 is completed, the clamp is released, the upper nip roller 38 is rotated, the weight 24 is wound up, and the weight 24 is pulled out of the furnace from the inlet of the tows 1 and 2. 38, the weight 24 is removed, the upper roller 38 of the nip roller 37 is moved upward, and the tows 1 and 2 held between the nip rollers 38 and 39 can be recovered.
Therefore, compared with the first embodiment, the start ends 1a and 2a and the end portions 1b and 2b of the tows 1 and 2 that have been made flame resistant can be easily recovered.

  The present invention is not limited to the above-described embodiment, and any device that can realize the above-described cross-sectional shape of the tow, the tension during heating of the tow, the wind speed of the hot air in the furnace, and the heating temperature in the furnace. Good. Moreover, you may provide toe width | variety control means, such as the groove | channel which restrict | limits a tow | toe width | variety, in the part which clamps the tow | toe of a clamp. Further, a groove for regulating the tow width may be formed on the surface of the guide roller. Further, the elastic part is not limited to one using a compression spring, and any elastic part may be used. For example, by using a constant load spring instead of the compression spring of the elastic part, a more stable tension F can be applied. The tow of the carbon fiber precursor may be an aggregate tow.

Next, an embodiment of the present invention will be specifically shown and described in detail.
First, the end of the carbon fiber precursor, which is an aggregated tow (filament number: 180,000) obtained by assembling three acrylic fibers (small tow) having a single yarn fineness of 1.0 dtex / filament and a filament number of 60000, is formed into a small tow with a fineness of 6000 tex. Divided.
And the width | variety of each small tow | toe was prescribed | regulated to 30 mm with the above-mentioned edge part flameproofing processing apparatus. At this time, the tow width per unit fineness of each small tow is 5.0 × 10 ⁻³ mm / tex.

Further, a load of 39 N was applied to each small tow so that the tension per unit fineness was 6.5 mN / tex by the above-described end flameproofing apparatus.
Next, the upper part of the end flameproofing furnace is opened and moved to a predetermined position to set the start and end parts of the carbon fiber precursor at a predetermined position in the furnace. Then, the upper part is closed, and hot air at 250 ° C. Heating was performed in a furnace circulating at a wind speed of 2 m / s to obtain a flame-resistant tow having a density of 1.40 g / cm ³ .

  As a result of flameproofing treatment under the conditions of the above-mentioned cross-sectional shape of the tow, tension during heating of the tow, wind speed of the hot air in the furnace, and heating temperature in the furnace, fusion between filaments, burnout of the tow, etc. The end portion of the carbon fiber precursor housed in the box could be flameproofed without being generated. At this time, the time required for flame resistance of the carbon fiber precursor was 47 minutes.

(Comparative Example 1)
The tow of the carbon fiber precursor is the same as that of Example 1 described above, the tow width of each small tow is defined as 30 mm, and the tow width per unit fineness is 5.0 × 10 ⁻³ mm / tex. It was. However, when the tow is introduced into the end flameproofing furnace, the above-mentioned end flameproofing apparatus is not used, and a yarn that does not burn in the furnace, such as a yarn such as carbon fiber, is connected to the tow, and the yarn is Tow was introduced into the furnace by towing.
At this time, the tension per unit fineness applied to the tow fluctuated in the range of 1.5 to 5.0 mN / tex due to fluctuations in the speed of pulling the yarn.
As a result, shrinkage and twisting of the tow due to heat entered, and heat was stored in the portion where the thickness of the tow increased, resulting in burnout, and flame resistance treatment could not be performed. At this time, the temperature in the furnace was 250 ° C.

(Comparative Example 2)
The carbon fiber precursor tow was the same as in Example 1 described above, and the tow width of each small tow was 30 mm, and the tow width per unit fineness was 5.0 × 10 ⁻³ mm / tex. However, the above-described end flameproofing device was not used, and the non-combustible yarn was connected to the tow as in Comparative Example 1, and the tow was introduced into the furnace by pulling the yarn. At this time, the temperature inside the end flameproofing furnace was lowered to 100 ° C. in order to prevent tow burnout.
After inserting the tow into the furnace, a load of 39 N was applied to the tow as in Example 1, the tension per unit fineness was 6.5 mN / tex, and hot air at 250 ° C. was circulated at a wind speed of 2 m / s. Heating was performed in a furnace to obtain a flame-resistant tow having a density of 1.40 g / cm ³ .
As a result, the end portion of the carbon fiber precursor could be flameproofed, but the furnace temperature was lowered when the tow was inserted, so the time required for flameproofing increased by 40 minutes compared to Example 1.

(Comparative Example 3)
The tow of the carbon fiber precursor was the same as in Example 1 described above, and the tow was flameproofed under the same conditions as in Example 1 except that the tow width of each small tow was defined as 10 mm. At this time, the tow width per unit fineness of each small tow is 1.7 × 10 ⁻³ mm / tex.
As a result, since the thickness of the tow was increased, the heat could not be removed and the heat was stored and burnt out, and the tow could not be flameproofed.

(Comparative Example 4)
The tow was flameproofed under the same conditions as in Example 1 except that the load applied to the tow was 9N. At this time, the tension per unit fineness is 1.5 mN / tex.
As a result, the tow contracted due to heat and the thickness increased, and the heat was stored and burned out, making it impossible to flame-proof the tow.

(Comparative Example 5)
The tow was flameproofed under the same conditions as in Example 1 except that the load applied to the tow was 180 N. At this time, the tension per unit fineness is 30 mN / tex.
As a result, the tow was out of tension and could not be flameproofed.

(Comparative Example 6)
The tow flameproofing treatment was performed under the same conditions as in Example 1 except that the wind speed of the hot air circulating in the end flameproofing furnace was 0.7 m / s.
As a result, it became difficult to remove the heat due to the heat of reaction of the tow flame, causing burnout, and the tow could not be flame-resistant.

It is a schematic sectional drawing of the whole structure of the edge part flame-proof apparatus in 1st embodiment of this invention. It is a schematic plan view of the whole structure of the edge part flame-proof apparatus in 1st embodiment of this invention. It is a schematic perspective view of the edge part flameproofing furnace in 1st embodiment of this invention. It is a schematic sectional drawing of the edge part flameproofing furnace in 2nd embodiment of this invention. It is a schematic exploded view of the jig | tool in 2nd embodiment of this invention. It is a schematic sectional drawing of the edge part flameproofing furnace in 3rd embodiment of this invention. It is a schematic sectional drawing of the edge part flameproofing furnace in 4th embodiment of this invention.

Explanation of symbols

1 Carbon fiber precursor (tow)
2 Carbon fiber precursor (tow)
3, 3a, 3b End flameproofing furnace 4 Toe inlet 5 Toe outlet 6 Moving means 7 Upper part 8 Lower part 11, 12 Box 13, 14, 15 Roller 16 Tow width regulating plate 17 Base 22, 23 Guide roller 25 Jig 26 Tool frame 27 Holding plate 28 Guide rail 29 Toe width adjusting plate 30 Notch portion 31 Fixing portion 32 Elastic portion 33 Shaft 34 Hole 35 Spring 37 Nip roller 38 Upper roller 39 Lower roller

Claims (1)

Before obtaining a continuous tow by joining the end portion of the tow that is a carbon fiber precursor and the start end portion of another tow, a flameproofing treatment method for making the start end portion and the end portion of the tow flame resistant,
The tow width per unit fineness of the tow is in the range of 2.0 × 10 ⁻³ mm / tex to 5.0 × 10 ⁻³ mm / tex, and the tension per unit fineness of the tow is 2.0 mN / tex. Hot air having a wind speed of 1.0 m / s or more and 4.0 m / s or less while applying a constant tension in the range of 25.0 mN / tex or less by fixing a weight to the end of the tow. oxidization processing method comprising treating flame the beginning and end of the toe and at a constant temperature by 2 5 0 ° C. Thus.

Images