Patent Application
20130340207
The invention relates to a pressure steam treatment apparatus of a carbon fiber precursor fiber bundle including a polyacrylonitrile or the like, and a producing method of the carbon fiber precursor fiber bundle.
In a producing of a carbon fiber or the like, as a precursor, for example, a fiber bundle made of a polyacrylonitrile polymer is employed as a fiber, and the fiber bundle is required to be excellent in a strength and a degree of orientation. Such a fiber bundle can be obtained, for example, by fiber spinning a fiber spinning solution including a polyacrylonitrile polymer so as to form a coagulated fiber, obtaining a densified fiber bundle by drawing in a bath and drying the coagulated fiber, and thereafter carrying out a secondary drawing treatment of the fiber bundle under a pressure steam atmosphere.
In the treatment of the fiber bundle under the pressure steam atmosphere, there is used a treatment apparatus which makes the fiber bundle travel inside of the apparatus and supplies a pressure steam with respect to the fiber bundle. In such a treatment apparatus, if the pressure steam supplied to the inside of the apparatus leaks out in large quantities to the outside of the apparatus from an inlet and an outlet of the fiber bundle, a pressure, a temperature, a humidity and the like in the inside of the apparatus becomes unstable, and there has been a case that a fuzz, a broken thread or the like is generated in the fiber bundle. Further, a lot of pressure steam is necessary for suppressing an influence of the leakage of the pressure steam to the outside of the apparatus, and an increase of an energy cost has been caused.
As a treatment apparatus which suppresses the leakage of the pressure steam from the inside of the apparatus, for example, Japanese Patent Application Laid-Open No. 2001-140161 (Patent Document 1), discloses a pressure steam treatment apparatus which is provided with a pressure steam treatment chamber which treats a fiber bundle traveling in a fixed direction by a pressure steam, and two labyrinth sealing chambers which extend from front and rear sides of the pressure steam treatment chamber. The labyrinth sealing chamber is provided with labyrinth nozzles in multiple stages in parallel along a fiber bundle travel path, the labyrinth nozzles being configured from plate pieces extending perpendicularly toward the fiber bundle from inner wall surfaces of a top plate and a bottom plate which are opposed to each other. An energy is consumed at a time of passing through each of spaces (expansion chambers) between the labyrinth nozzles, whereby an amount of leakage of the pressure steam is lowered.
According to the Patent Document 1, the first and second labyrinth sealing chambers are arranged in the front and rear sides of the pressure steam treatment chamber, and a plurality of fiber bundles traveling in parallel like a sheet along the fiber bundle travel path are treated under the pressure steam atmosphere in a lump. A value of a ratio (L/P) between an extension length L of the labyrinth nozzle from the inner wall surfaces of the top plate and the bottom plate, and a pitch P between the front and rear nozzles is between 0.3 and 1.2, and a number of the stages of the labyrinth nozzles is set to 80 to 120 in both of a first and a second labyrinth sealing chambers in the front and rear sides. Further, a filling factor F of the fiber bundle calculated by the following expression in the fiber bundle travel path within the labyrinth sealing chamber is set to 0.5 to 10%.
filling factor F={K/(ρ×105)}/A
Here, K: fiber bundle fineness (tex)
Since a magnitude of an expansion chamber formed between the front and rear nozzles comes to a preferable one by setting the value of L/P to the range, and it is possible to extremely consume the energy by repeating generation and elimination of a small eddy current of a rotation within the expansion chamber, a decompression effectively makes progress. It is possible to effectively suppress a team leakage amount in cooperation with the number of the forming stages of the labyrinth nozzles such as 80 to 120 stages, and it is possible to effectively prevent a damage of the fiber bundle and the fuzz.
Patent Document 1: Japanese Patent Application Laid-Open No. 2001-140161
According to the pressure steam treatment apparatus described in the Patent Document 1, a plurality of fiber bundles travel in parallel along the fiber bundle travel path, however, since each of the adjacent fiber bundles at this time travels simply in a parallel state, the adjacent fiber bundles interfere with each other if the filling factor of the fiber bundle passed through the treatment apparatus goes beyond 10%, and a combined filament tends to be generated.
Further, in this kind of pressure steam treatment apparatus according to the prior art, when a broken thread is generated in the inside of the pressure steam treatment apparatus in one spindle of a plurality of fiber bundles, the broken fiber bundle is left in the labyrinth sealing chamber, and is disturbed by the steam so as to be confounded with the adjacent fiber bundle, and the broken thread is induced, thereby causing a reduction of a yield ratio.
Further, the high pressure steam introduced from the pressure steam treatment chamber in the center flows into and fills inside of the pressure steam treatment chamber and the first and second labyrinth sealing chambers which are arranged in the front and rear sides. At this time, the pressure steam does not flow in a determined direction, and there is a high possibility that it tends to flow in such a direction as to confound the adjacent fiber bundles. As a result, the broken yarn as mentioned above is further contributed, and there is accordingly a high risk that it becomes hard to uniformly and stably burn in the carbon forming step thereafter.
The invention is made to solve the conventional problem, and an object of the invention is to provide a pressure steam treatment apparatus of a carbon fiber precursor fiber bundle which can suppress an influence of a leakage of a pressure steam to the outside of the apparatus so as to hold down a pressure steam supply amount to the minimum, simultaneously reduce a broken yarn, improve a yield ratio, and have a high productivity.
The object mentioned above can be effectively achieved by a pressure steam treatment apparatus of a fiber bundle which is provided with a pressure steam treatment chamber and labyrinth sealing chambers, and treats a plurality of fiber bundles traveling in parallel under a pressure steam atmosphere in a lump, being characterized in that the labyrinth sealing chambers are continuously provided in an inlet and an outlet of the fiber bundle of the pressure steam treatment chamber respectively, and fiber bundle travel paths in the labyrinth sealing chambers are comparted per each of the fiber bundles, which corresponds to a first basic structure of the invention.
Further, the object can be effectively achieved by a producing method of a carbon fiber precursor fiber bundle being characterized in that a plurality of fiber bundles are drawn by the pressure steam treatment apparatus in a lump, which corresponds to a second basic structure of the invention.
According to a preferable aspect of the invention, it is preferable that a plurality of partition plates are continuously provided in parallel to a fiber bundle per each of stages of the labyrinth nozzle and along between the adjacent fiber bundles in the fiber bundle parallel direction, in the labyrinth sealing chamber. Further, it is desirable to have the partition plates in parallel to the fiber bundle and along between the adjacent fiber bundles in the fiber bundle parallel direction, in the labyrinth sealing chamber. In the labyrinth sealing chamber, a plurality of partition plates may be continuously provided in parallel to the fiber bundle between the labyrinth nozzle and the adjacent labyrinth nozzle, and along between the adjacent fiber bundles in the fiber bundle parallel direction.
It is preferable that the partition plate is provided between an optional labyrinth nozzle and an adjacent labyrinth nozzle. Further, it is preferable that a length of the partition plate in parallel to the fiber bundle is between 55 and 95% of a height between a surface of an optional labyrinth nozzle and an opposed surface of an adjacent labyrinth nozzle. The partition plate may be provided in an inner surface of the upper or lower labyrinth plate. There is a case that the height of the partition plate is equal to or more than a sum of a height (L) of the labyrinth nozzle and an opening height (H) between the upper end lower labyrinth nozzles. Further, the partition plate may be provided in the inner surfaces of the upper and lower labyrinth plates.
It is preferable that the partition plates provided in the inner surfaces of the upper and lower labyrinth plates are at the opposed positions, and a height of one of the partition plates provided in the upper and lower labyrinth plates is equal to or more than a sum of the height of the upper or lower labyrinth nozzle and the opening height between the upper and lower labyrinth nozzles. Further, the partition plates provided in the inner surfaces of the upper and lower labyrinth plates are at position where not interfering with each other between the same fiber bundles, and the sum of the heights of the partition plates provided in the inner surfaces of the upper and lower labyrinth plates may be made equal to or more than the height from the inner surface of the upper labyrinth plate to the inner surface of the lower labyrinth plate.
On the basis of a steam rectifying effect achieved by dividing the fiber bundle travel path of the labyrinth sealing chamber into several paths in parallel to the fiber bundle and orthogonal to the fiber bundle parallel direction, a fiber bundle travel stability is improved in the inside of the pressure steam treatment apparatus, and a contact and a confounding between the adjacent fiber bundles can be considerably reduced. Before reaching the invention, a test which comparts the fiber bundle travel path by a pin guide has been carried out. However, since a fuzz piles up between the pin guide and the labyrinth nozzle, it is necessary to frequently carry out a removing work to remove the fuzz, and since an induced breakage is successively generated, a step stability can not be secured, and it has been found that it was difficult to put it to practical use. Further, a diameter of the pin guide has been tried to be thicker in order to reduce the generation of the fuzz pile, however, it has been indispensable to make the fiber bundle travel path narrower, and a productivity is lowered, so that it can not be put to practical use.
As one of preferable aspects of the invention, particularly, it is known that if the partition plate is used for a dividing means, the induced breakage can be effectively prevented in the inside of the pressure steam treatment apparatus. As a result, not only the fiber bundle having a reduced fuzz and having a high quality can be obtained, but also a travel stability of the fiber bundle is maintained, so that a yield ratio is significantly improved. The arranged position and the magnitude of the partition plate with respect to the labyrinth nozzle or the labyrinth plate are various as mentioned above.
An embodiment of the invention will be particularly described below with reference to the accompanying drawings. Before describing the embodiment of the invention, an outline structure will be described by exemplifying a conventional typical pressure steam treatment apparatus shown in
A pressure steam treatment apparatus 1 shown in
As a material of a member which constructs the pressure steam treatment apparatus 1, any structure material can be applied as long as the material has a sufficient mechanical strength for carrying out a seal for preventing a leakage of a steam, and is not particularly limited. For example, as a material of a portion which may come into contact with the fiber bundle in an inner surface of the treatment apparatus, there is employed a material obtained by applying a hard chrome plating treatment to a stainless steel or a steel material in such a manner that it is possible to suppress a damage applied to the fiber bundle in the case of being contact as much as possible, as well as to have a corrosion resistance.
The pressure steam treatment chamber 2 has pressure chambers 2a in upper and lower sides while holding the fiber bundle travel path 5 between them, as shown in
The labyrinth sealing chamber 3 is configured from labyrinth nozzles 3a in a multiple stages in a longitudinal direction of the fiber bundle, as shown in
The labyrinth nozzles 3a extend vertically toward the travel fiber bundle Y from all the inner wall surfaces in upper and lower and right and left of the labyrinth sealing chamber 3, and are arranged in a multiple stages between 80 stages and 120 stages in a longitudinal direction of the fiber bundle Y, and an expansion chamber 3c is formed between the labyrinth nozzles 3a in the back and forth in the fiber bundle longitudinal direction. An energy is consumed at a time of passing through each of the spaces (the expansion chambers) 3c between the labyrinth nozzles 3a, whereby a leaking amount of a pressure steam is lowered.
The labyrinth nozzle 3a is configured from a tabular plate piece having a uniform thickness, and a slit-like opening 3b extending in a horizontal direction is formed in the center in a height direction, as shown in
Any other member is not provided in the inside of the opening 3b, and is open continuously in a back and forth direction of the labyrinth sealing chamber 3, as show in
The invention is characterized in that a structure of a fiber bundle travel path 5′ of the labyrinth sealing chamber 3 is different from the conventional fiber bundle travel path 5. In other words, according to the invention, as shown in
The partition plate 3e is arranged over a whole length of the upper end lower inner wall surfaces in a space (an expansion chamber 3c′) between the labyrinth nozzles 3a. In the present embodiment, the partition plate 3e configured from the flat plate piece which is independent from the labyrinth nozzle 3a constructing the labyrinth sealing chamber 3 and the upper and lower labyrinth plates 3d is separately attached, however, it may be integrally formed directly in the upper and lower labyrinth plates 3d, for example, similar to the labyrinth nozzle 3a, or may be integrally formed directly in the labyrinth nozzle 3a. As a material of the partition plate 3e, there is used a plate material obtained by applying a hard chrome plating treatment to a stainless steel, a titanium, a titanium alloy or a steel material.
In the present embodiment, as shown in
In order to draw the fiber bundle under a pressure steam atmosphere by using the pressure steam treatment apparatus 1, first of all, a thread is passed through the apparatus 1. In this case, in the pressure steam treatment apparatus disclosed in the Patent Document 1, in order to improve a thread passing performance, it is divided into two pieces so as to be divided up and down by a plane including the fiber bundle travel path 5. The same structure can be employed in the invention. According to this structure, the thread passing performance is improved particularly in the case that a lot of spindles are treated in a lump, and it is possible to carry out the thread passing work easily and for a short time.
Further, in the invention, in the same manner as the pressure steam treatment apparatus disclosed in the Patent Document 1, it is preferable to set an introducing amount of the fiber bundle to the pressure steam treatment apparatus 1 in such a range that a filling factor F is between 0.5% and 10%. The filling factor F is a value which is determined by the following expression F={K/(ρ×105)}/A, that is, a rate occupied by a fiber bundle cross sectional area with respect to an opening area of the opening 3b in the labyrinth sealing chamber 3. In this case, K is a fiber bundle fineness (tex), ρ is a fiber bundle density (g/cm3), and A is an opening area (cm2) of the fiber bundle travel path.
A drawing treatment is applied to the fiber bundle under the pressure steam atmosphere by supplying the steam to the pressure steam treatment chamber 2 from the steam introduction port. At this time, the steam in the inside of the apparatus is going to leak out to the outside from the fiber bundle inlet 4 and the fiber bundle outlet 6. In the invention, in the same manner as the pressure steam treatment apparatus disclosed in the Patent Document 1, the labyrinth sealing chamber 3 is arranged in each of the inlet and the outlet of the fiber bundle in the pressure steam treatment chamber 2, and if the labyrinth nozzles 3a are formed in a multiple stages between 80 stages and 120 stages in the sealing chamber 3, and the ratio (L/P) of the extending length L of the labyrinth nozzle 3a, that is, the length L to the opening 3b, and the pitch P between the front and rear nozzles is set to 0.3 to 1.2, it is possible to further effectively prevent the leakage of the steam.
The labyrinth nozzle 3a can effectively reduce the steam leakage amount by setting the forming stage number to 80 stage to 120 stage. In the case that the number of the labyrinth nozzles is less than 80 stages, the sealing performance becomes insufficient, and even if the number of the labyrinth nozzles is made equal to or more than 120 stages, the effect of suppressing the steam leakage does not change.
Further, the labyrinth nozzle 3a can effectively suppress the leakage of the steam by setting the value of the ratio (L/P) of the extending length L from the inner wall surfaces of the upper end lower labyrinth plates 3d and the pitch P between the adjacent nozzles to be in a range between 0.3 and 1.2. It is possible to effectively suppress the steam leakage amount by adjusting the value of the L/P as mentioned above so as to optimize a dimension and a cross sectional shape of the expansion chamber 3c′, and it is possible to effectively prevent a damage of the fiber bundle and a fuzz.
A ratio H/W of a height of the vertical opening with respect to a lateral width W of the opening 3b is set to 1/900 to 1/100 in the same manner as the pressure steam treatment apparatus described in the Patent Document 1. If the ratio H/W is equal to or less than 1/900, a generation of the damage of the fiber bundle and the fuzz can not be suppressed, and if the ratio H/W is equal to or more than 1/100, it is difficult to keep the fiber bundle flat and suppress the steam leaking amount at the same time.
Further, it is possible to prevent an interference between the fiber bundles traveling in adjacent in the multiple spindle treatment and a damage and a combined filament accompanying with it, by suppressing the filling factor F in conjunction with setting the value of the ratio H/W of the vertical opening height H with respect to the width W of the slit-like opening 3b to 1/900 to 1/100. It is preferable that the filling factor F is set to 0.5% to 10%. If the filling factor F is less than 0.5% or if the number of the labyrinth nozzles 3a is less than 80 stages, the leakage amount of the steam is increased, and if the filling factor F goes beyond 10%, or the number of the labyrinth nozzles 3a goes beyond 120 stages, a contact between the fiber bundle and the labyrinth nozzle 3a can not be disregarded, and the combined filament between the adjacent fiber bundles or the constructing fibers tends to be generated.
Further, since the present embodiment employs the labyrinth nozzle 3a in which the shape of the opening 3b constructing the fiber bundle travel path 5′ in the labyrinth sealing chamber 3 is the slit shape as shown in
In the pressure steam treatment apparatus described in the Patent Document 1, in the case of using the pressure steam treatment apparatus in which the apparatus main body can be divided in the fiber bundle parallel direction in the flat surface including the fiber bundle travel path 5, it is preferable that the gap is provided between the labyrinth nozzle 3a and the partition plate 3e, as exemplified in
By making the length in the fiber bundle longitudinal direction of the partition plate equal to or more than 55% of the height of the surface of the optional labyrinth nozzle 3a and the opposed surface of the adjacent labyrinth nozzle, it is possible to prevent the contact and the intertwining between the adjacent fiber bundles Y, prevent the fuzz and the combined filament from being generated in the labyrinth sealing chamber 3 and further prevent the induced breakage from being generated by the confounding between the adjacent fiber bundles Y, the travel stability of the fiber bundle Y becomes significantly improved, the yield ratio becomes high, and it is possible to obtain the high-quality fiber bundle which is excellent in the productivity and generates less fuzz. By making the length in the fiber bundle longitudinal direction of the partition plate equal to or less than 95% of the height of the surface of the optional labyrinth nozzle and the opposed surface of the adjacent labyrinth nozzle, it is possible to prevent the labyrinth nozzle in a side having no partition plate in the upper or lower labyrinth nozzles from coming into contact with the partition plate at a time of closing the pressure steam apparatus which is divided in the flat surface including the fiber bundle travel path 5, and the breakage between the labyrinth nozzle and the partition plate is not generated.
The pressure steam treatment apparatus 1 according to the embodiment is structured so as to travel the fiber bundle in the horizontal direction, however, the traveling direction is not limited to the horizontal direction, but it is possible to construct a treatment apparatus of a type of traveling in a vertical direction. Further, there is shown the example in which the partition plate 3e is provided in each of the labyrinth sealing chambers 3 which are arranged respectively in the inlet and the outlet of the fiber bundle of the pressure steam treatment chamber 2, however, the partition plate 3e may be arranged only in the labyrinth sealing chamber 3 in either of the inlet or the outlet of the fiber bundle of the pressure steam treatment chamber 2. In this case, it is preferable to arrange the partition plate 3e in the labyrinth sealing chamber 3 at least in the inlet side of the fiber bundle.
Further, in the embodiment, the labyrinth nozzle 3a is extended from all the inner wall surfaces in upper and lower and right and left of the labyrinth sealing chamber 3, and a whole periphery of the fiber bundle travel path 5 is surrounded by the labyrinth nozzle 3, however, the embodiment is not limited to the structure mentioned above. There is a case that the labyrinth nozzle 3a maybe extended, for example, only from the upper and lower wall surfaces, not from all the surfaces of the inner wall surface, and in this case, the fiber bundle travel path 5′ is surrounded by the labyrinth nozzle 3a which is extended vertically from the upper and lower labyrinth plates 3d and the right and left side wall surfaces of the labyrinth sealing chamber 3.
A fiber spinning solution is adjusted by resolving a polyacrylonitrile polymer obtained by copolymerizing an acrylonitrile (AN), a methyl acrilate (MA) and a methacrylic acid (MAA) at a mole ratio AN/MA/MAA=96/2/2 in a dimethyl acetamide (DMAc) solution (a polymer concentration of 20% by mass, a viscosity of 50 Pa·s, a temperature of 60° C.), and the fiber spinning solution is discharged to a DMAc water solution at a concentration of 70% by mass and a liquid solution of 35° C. through a fiber spinning mouth piece having a hole number of 12000 so as to be water washed, is thereafter drawn to three times in a hot water bath, and is dried at 135° C., whereby a densified fiber bundle F is obtained.
The invention will be more specifically described below on the basis of embodiments and comparative examples. The embodiments and the comparative examples described below are only exemplifications, and the invention is not limited to the following description.
In the following embodiments and comparative examples, there is employed a pressure steam treatment apparatus 1 which is improved on the basis of the conventional pressure steam treatment apparatus shown in
In the treatment apparatus 1 exemplified in
The pressure steam treatment was carried out by introducing the fiber bundle Y obtained in the producing example 1 at three spindles from the fiber bundle inlet, using the treatment apparatus 1. The pressure of the pressure chamber was set to 300 kPa, and a drawing magnification of the fiber bundle Y by the pressure steam was set to three times. The fiber spinning was carried out for ten hours at the same time of starting the drawing treatment by the pressure steam. During the fiber spinning of the fiber bundle, it was possible to stably steam draw without any flopping in all the fiber bundles and without any generation of fuzz. After ten hours has passed from starting producing of the fiber bundle, a waste thread was wound around the fiber bundle Y traveling in the center among the fiber bundles Y traveling in the inlet side of the treatment apparatus 1, and the fiber bundle Y traveling in the center was forcibly cut in the treatment apparatus 1, however, as shown in Table 1, the adjacent two fiber bundles Y were not thereafter cut in an induced manner, and the steam drawing could be stably carried out.
The pressure steam treatment of the fiber bundle Y was carried out for ten hours using the same pressure steam treatment apparatus 1 as the Embodiment 1, except for changing the length P1 in the fiber bundle longitudinal direction of the partition plate 3e of the treatment apparatus 1 as shown in Table 1. Further, the waste thread was wound around the fiber bundle Y traveling in the center among the fiber bundles Y traveling in the inlet side of the treatment apparatus 1 after ten hours has passed from starting producing of the fiber bundle, and the fiber bundle Y traveling in the center was forcibly cut in the treatment apparatus 1. Table 1 shows results obtained by observing the state of the fuzz of the fiber bundle after the pressure steam drawing during the execution of the drawing by the pressure steam treatment apparatus 1, and estimating a generation frequency of the fuzz, and a generation condition of the induced cut of two adjacent fiber bundles Y after forcibly cutting the fiber bundle Y traveling in the center. In the same manner as the Embodiment 1, it was possible to stably carry out the steam drawing without the generation of the fuzz and the induced cut.
As exemplified in
The pressure steam treatment of the fiber bundle Y was carried out for ten hours using the same treatment apparatus as the treatment apparatus 1 of the Embodiment 1, except that the upper and lower partition plates 3e having the different heights H1 and H2 and attached to the inner surfaces of the upper and lower labyrinth plates 3d were at positions not interfering with each other between the same adjacent fiber bundles, and a sum of H1+H2 of the heights of the partition plates which were arranged alternately in the inner surfaces of the upper and lower labyrinth plates was equal to or more than a height from the inner surface of the upper labyrinth plate 3d to the inner surface of the lower labyrinth plate 3d.
Further, the waste thread was wound around the fiber bundle Y traveling in the center among the fiber bundles Y traveling in the inlet side of the treatment apparatus 1 after ten hours has passed from starting producing of the fiber bundle, and the fiber bundle Y traveling in the center was forcibly cut in the treatment apparatus 1. Table 1 shows results obtained by observing the state of the fuzz after the pressure steam drawing during the execution of the drawing by the pressure steam treatment apparatus, and estimating a generation frequency of the fuzz, and a generation condition of the induced cut of two adjacent fiber bundles Y after forcibly cutting the fiber bundle Y traveling in the center. As shown in Table 1, it was possible to stably carry out the steam drawing without the generation of the fuzz and the generation of the induced cut.
As exemplified in
As exemplified in
As mentioned above in detail, according to the pressure steam treatment apparatus of the fiber bundle of the invention, since it is possible to prevent the interference between the adjacent fiber bundles, and it is possible to uniformly apply the pressure steam to each of the fiber bundles, by dividing the fiber bundle travel path in the fiber bundle parallel direction, the traveling performance of the fiber bundle is improved, the leaking amount of the steam can be suppressed to the minimum, it is possible to carry out a stable pressure steam treatment with respect to each of the fiber bundles, and the high-quality fiber bundle without any damage and any fuzz can be obtained.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-052025 | Mar 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/053008 | 2/9/2012 | WO | 00 | 9/9/2013 |
