Patent Application
20190233977
The present disclosure relates to a carbon fiber pre-oxidization technology, in particular to disclose an oxidation fiber manufacturing method of helping to enhance the performance of the carbon fiber.
The carbon fiber is a new carbon material with 90% carbon concentration, in which the organic fiber is performed with sequential thermal processes to transform to such carbon fiber. The carbon fiber has advantages of the high specific strength, the high specific modulus, the high conductivity and the thermal conductivity, the low thermal expansion coefficient, the low density, the high temperature resistance, the fatigue resistance, the creep resistance and the self-lubrication, and is an ideal function and structure material being widely used in the aerospace, civil aviation and transportation and other fields, thus having wide application prospects.
The carbon fiber preparing process using polyacrylonitrile (PAN) as the raw silk comprises polymerization, spinning, pre-oxidization and carbonization processes, wherein the pre-oxidization process is the key structure transformation stage of in the carbon fiber preparing process, and is the most time consuming stage in the thermal processing processes, which has the objective of transforming the linear macromolecular chains of polyacrylonitrile to the oxidation fiber with the thermal resistance structure, such that the oxidation fiber in the next carbonization will not burned and melted, and can maintain the fiber shape.
The structure transformation of the raw silk in the pre-oxidization process mainly determines the structure and the performance of the carbon fiber. During the industrial production, the pre-oxidization process with gradient temperature increasing manner is mostly used, and the proper gradient temperature range in the process is required. If the initial temperature is too low, it will not contribute to the pre-oxidization process, and the consuming time will be increased to cause the large cost. By contrast, if the initial temperature is too high, the heat emission of the severe reaction will make the macromolecular chains of polyacrylonitrile be melted, wherein the macromolecular chains of polyacrylonitrile have no thermal resistance. In addition, if the termination temperature is too high, the concentrated heat emission destroys the structure of the pre-oxidization silk, and makes the pre-oxidization silk over oxidized, and thus it is hard to prepare the carbon fiber with high strength. However, if the termination temperature is too low, the raw silk is not pre-oxidized sufficiently.
Moreover, when the pre-oxidization process is performed by heating, accompanying with the progressing of the pre-oxidization, since the heat is transmitted from the outer layer of the raw silk to the inner layer of the raw silk, the outer layer of the raw silk is firstly formed with an oxidization layer (i.e. the shell portion) having compact trapezoidal structure, and this prevents the oxygen from diffusing to the core portion of the raw silk. As such, as shown in
Accordingly, the present disclosure provides an oxidation fiber manufacturing method which has the main objectives of shortening the oxidization time of the oxidation fiber, efficiently eliminating the shell-core structure of the oxidation fiber, and even making the oxidation fiber have no obvious shell-core structure.
The present disclosure provides an oxidation fiber manufacturing method used to pre-oxidize a fiber yarn bunch to form an oxidation fiber yarn bunch. The fiber yarn bunch is formed by merely one fiber, or alternatively, the fiber yarn bunch is formed by binding a plurality of fibers. The oxidation fiber yam bunch is formed by merely one oxidation fiber, or alternatively, the oxidation fiber yarn bunch is formed by binding a plurality of oxidation fibers. The oxidation fiber manufacturing method comprises following steps:
In one embodiment, an oxidation fiber manufacturing method of the present disclosure is used to pre-oxidize a fiber yarn bunch to form an oxidation fiber yarn bunch. The fiber yarn bunch is formed by merely one fiber, or alternatively, the fiber yarn bunch is formed by binding a plurality of fibers. The oxidation fiber yarn bunch is formed by merely one oxidation fiber, or alternatively, the oxidation fiber yarn bunch is formed by binding a plurality of oxidation fibers. the oxidation fiber manufacturing method comprises following steps:
According to the oxidation fiber manufacturing method, the fiber of the fiber yarn bunch is pre-oxidized to form the oxidation fiber by using the oxidation fiber manufacturing method.
According to the oxidation fiber manufacturing method, the microwaving condition comprises: a microwave frequency being 300 MHz through 300,000 MHz; a microwave power being 1 kW/m2 through 1000 kW/m2 ; an operation temperature being 100° C. through 600° C.; and a gas atmosphere being at least one of oxygen, air and ozone.
According to the oxidation fiber manufacturing method, a processing time is 1 minute through 40 minutes.
According to the oxidation fiber manufacturing method, the microwave power is 10 kW/m2 through 24 kW/m2 .
According to the oxidation fiber manufacturing method, the microwave frequency is 2000 MHz through 3000 MHz, the operation temperature being 150° C. through 350 and the processing time is 5 minutes through 20 minutes.
According to the oxidation fiber manufacturing method, he fiber yarn bunch is one of a polyacrylonitrile (PAN) fiber, a pitch fiber and other one organic fiber.
According to the oxidation fiber manufacturing method, the transmitting unit is installed with a feeding unit for providing the fiber yarn bunch, a winder unit for continuously pulling and transmitting the fiber yarn bunch, and an oven body which the fiber yarn bunch passes. The microwave processing unit is installed with a magnetron at the oven body for generating the microwave frequency and the microwave power, and is further installed with a gas supplying unit for injecting the gas atmosphere into the oven body.
According to the oxidation fiber manufacturing method, the winder unit, the magnetron and the gas supplying unit are electrically connected to a control unit.
According to the oxidation fiber manufacturing method, interior of the oven body is installed with a thermos unit.
According to the oxidation fiber manufacturing method, the thermos unit is at least one of a metal oxide, a carbide and a high microwave sensitive material.
According to the oxidation fiber manufacturing method, the fiber yarn bunch disposed is disposed in the oven body by a repeating and winding manner, and continuously irradiated by the microwave processing unit.
The oxidation fiber manufacturing method of the present disclosure mainly uses the microwave processing unit to focus the microwave to apply an ultra-fast pre-oxidization process on the fiber yarn bunch, such that the fiber yarn bunch is processed to form the oxidation fiber. Not only the oxidization time of the oxidation fiber can be shortened, but also the cross section area of the oxidation layer in the oxidation fiber occupies more than 50% of the cross section area of the oxidation fiber, which efficiently eliminate the shell-core structure. When the cross section area of the oxidation layer in the oxidation fiber occupies more than 80% of the cross section area of the oxidation fiber, even the oxidation fiber has no obvious shell-core structure. Accordingly, relatively positive and reliable means are provided to improve the performance of the carbon fiber.
The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
The present disclosure mainly provides an oxidation fiber manufacturing method which can shorten the oxidization time of the oxidation fiber, efficiently eliminate the shell-core structure of the oxidation fiber, and even make the oxidation fiber have no obvious shell-core structure. As shown in
Step A: providing a transmitting unit 30 and a microwave processing unit 40. When the present disclosure is implemented, the transmitting unit 30 is installed with a feeding unit 31 for providing the fiber yarn bunch 20, a winder unit 32 for continuously pulling and transmitting the fiber yarn bunch 20, and an oven body 33 which the fiber yarn bunch 20 passes, wherein the fiber yarn bunch 20 is formed by merely one fiber (not shown in the drawings), or alternatively, the fiber yarn bunch 20 is formed by binding a plurality of fibers. The microwave processing unit 40 is installed with a magnetron 41 at the oven body 33 for generating the microwave, and is further installed with an gas supplying unit 42 for injecting a gas atmosphere into the oven body 33. The gas supplying unit 42 is coupled to a gas inlet 331 of the oven body 33, and the gas with the oxygen is injected into the oven body 33 via the gas inlet 331, and exhausted from the oven body 33 via a gas outlet 332 of the oven body 33. The transmitting unit 30 is further installed with a thermos unit 34 in the interior of the oven body 33. Preferably, the microwave processing unit 40 is installed with the plurality of the magnetrons 41 at the oven body 33. The magnetrons 41 are disposed at the top and bottom sides of the oven body 33, and the magnetrons 41 disposed on the top and bottom sides of the oven body 33 are arranged corresponding to each other or in an offset manner, or alternatively, the magnetrons 41 are disposed at single one side of the oven body 33 (such as the top or bottom side). As shown in
Step B: providing the fiber yarn bunch 20, disposing the fiber yarn bunch 20 in the transmitting unit 30, and making the transmitting unit 30 drive the fiber yarn bunch 20 to pass the microwave processing unit 40. For example, the winded fiber yarn bunch 20 can be disposed at the transmitting unit 30 by the manner that the winded fiber yarn bunch 20 can be continuously driven by the transmitting unit 30 to pass the operation region of the microwave processing unit 40. In the embodiment, the winded fiber yarn bunch 20 is disposed at the feeding unit 31, and the tail end of the fiber yarn bunch 20 is guided to pass the oven body 33 and then fixed on the winder unit 32, wherein the fiber yarn bunch 20 can be one of a polyacrylonitrile (PAN) fiber, a pitch fiber and other one organic fiber.
Step C: activating the microwave processing unit 40, and using the microwave processing unit 40 to generate a microwaving condition. The microwaving condition comprises: a microwave frequency being 300 MHz through 300,000 MHz; a microwave power being 1 kW/m2 through 1000 kW/m2 ; an operation temperature being 100° C. through 600° C.; and a gas atmosphere being at least one of oxygen, air and ozone. The gas atmosphere is the above gas with oxygen. In the embodiment, the gas supplying unit 42 is used to inject the gas with oxygen into the interior of the oven body 33.
Step D: activating the transmitting unit 30, using the transmitting unit 30 to drive the fiber yarn bunch 20 to be exposed in the microwaving condition for a processing time, so as to transform the fiber yarn bunch 20 to the oxidation fiber yarn bunch 20A. For example, the fiber yarn bunch 20 is driven by the transmitting unit 30 to pass the operation region of the microwave processing unit 40 at the speed which the microwave focusing process is continuously applied for 1 minute through 40 minutes, and that is, the processing time is 1 minute through 40 minutes. In the embodiment, the fiber yarn bunch 20 is driven by the transmitting unit 30 to pass the oven body 33 to form the oxidation fiber yarn bunch 20A at the speed which the microwave focusing process is continuously applied for 1 minute through 40 minutes. In addition, the fiber yarn bunch 20 in the oven body 33 is winded and repeated to pass the oven body 33 to the oxidation fiber yarn bunch 20A at the speed which the microwave focusing process is continuously applied for 1 minute through 40 minutes, so as to form the oxidation fiber yarn bunch 20A. For example, the fiber yarn bunch 20 at the front end of the oven body 33 enters the interior of the oven body 33, and then is transmitted to the back end of the oven body 33. Next, the fiber yam bunch 20 is transmitted from the back end of the oven body 33 to the front end of the oven body 33, and then is transmitted from the front end of the oven body 33 to the back end of the oven body 33 again. The manner is used to repeat and wind the fiber yarn bunch 20 until the requirements is satisfied, and then the fiber yarn bunch 20 is sent out from the back end of the oven body 33 to form the oxidation fiber yarn bunch 20A. The above used repeating and winding manner can sufficiently reduce the required length of the oven body 33.
Accordingly, by using oxidation fiber manufacturing method, under the operation of the transmitting unit 30, the fiber yarn bunch 20 is driven to pass the operation region of the microwave processing unit 40 at the predetermined speed. During the progress which the fiber yarn bunch 20 passes the operation region of the microwave processing unit 40, the microwave focusing is continuously used to apply the ultra-fast pre-oxidization process on the fiber yarn bunch 20, so as to process the fiber yarn bunch 20 to form the oxidation fiber yam bunch 20A. As shown in
Referring to
Referring to
Refer to Table 1 and Table 2 simultaneously. Table 1 is a comparison table showing the measured tensile strengths of the fiber yam bunches 20, the oxidation fiber yarn bunches 20A and the carbon fiber yarn bunches formed by the next carbonization, wherein two sets of the fiber yarn bunches 20, the oxidation fiber yarn bunches 20A and the carbon fiber yarn bunches are respectively processed by the conventional electro thermal tube heating process and the microwaving process of the oxidation fiber manufacturing method of the present disclosure. Table 2 is a comparison table showing the measured tensile moduli of the fiber yam bunches 20, the oxidation fiber yarn bunches 20A and the carbon fiber yarn bunches formed by the next carbonization, wherein two sets of the fiber yarn bunches 20, the oxidation fiber yarn bunches 20A and the carbon fiber yarn bunches are respectively processed by the conventional electro thermal tube heating process and the microwaving process of the oxidation fiber manufacturing method of the present disclosure. Regarding the conventional electro thermal tube heating process, the processing condition is the oven body temperature of 270° C. and the p g time of 40 minutes,and the obtained results of the physical properties are called “comparative example 1”. Regarding the microwaving process of the oxidation fiber manufacturing method of the present disclosure, the processing condition is the oven body temperature of 220° C., the microwave frequency of 2450 MHz, the microwave power of 24 kW/m2 and the processing time of 10 minutes, and the obtained results of the physical properties are called “embodiment 1”. In both of the comparative example 1 and the embodiment 1, the fiber yarn bunches 20 are made of polyacrylonitrile.
In Table 1, the embodiment 1 shows the tensile strength of the final carbon fiber yarn bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the oxidation fiber manufacturing method of the present disclosure is 1.3 times of that in the comparative example 1 (i.e. 3675 divides 2824), and that is the tensile strength has the improvement of 30%. The microwaving process can oxidize polyacrylonitrile more complete, and the tensile strength of the oxidation fiber yarn bunch associated with the microwaving process is slightly less than that of the oxidation fiber yarn bunch associated with the conventional electro thermal tube heating process, which is another one evidence that the microwaving process of the oxidation fiber manufacturing method of the present disclosure can further increase the oxidization degree of the fiber yam bunch.
In Table 2, embodiment 1 shows the tensile modulus of the final carbon fiber yarn bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the oxidation fiber manufacturing method of the present disclosure is 1.17 times of that in the comparative example 1 (i.e. 227.1 divides 194.4), and that is the tensile modulus has the improvement of 17%.
Accordingly, compared with the oxidation fiber yarn bunches respectively generated by the fiber yarn bunches on which the conventional heating process and the microwaving process of the present disclosure are performed, the microwaving process of the present disclosure can reduce the required time of the conventional heating process from 40 minutes to 10 minutes, thus the process efficiency is increased with three times, and the process time is reduced. Compared to the conventional heating process, the present disclosure can enhance the 30% tensile strength and the 17% tensile modulus of carbon fiber yarn bunch. Compared to the conventional heating process, the present disclosure can further make the cross section area of the oxidation layer 2111 of the oxidation fiber 21 in the oxidation fiber yarn bunch 20A occupy more than 99.0% of the cross section area of the oxidation fiber 21, such that no obvious shell-core structure exists. The cross section of the oxidation fiber yarn bunch 20A is more uniform, and thus the tensile strength and the tensile modulus of the carbon fiber yarn bunch are increased. The relatively positive and reliable means for enhancing the carbon fiber performance are therefore provided.
When the oxidation fiber manufacturing method of the present disclosure is implemented, the 24 kW/m2 microwave focusing process is applied to process the fiber yarn bunch for 5 minutes through 10 minutes, preferably. Certainly, when the oxidation fiber manufacturing method of the present disclosure is implemented, the 24 kW/m2 microwave focusing process is applied to process the fiber yarn bunch for 5 minutes through 10 minutes. As shown in
Certainly, the oxidation fiber manufacturing method of the present disclosure can also be adapted to the batch generation manner. The embodiment of the batch generation manner can sequentially execute the following steps, as shown in
A yarn bunch providing step S01: preparing the fiber yarn bunch 20. The fiber yarn bunch 20 is formed by merely one fiber, or alternatively, the fiber yarn bunch 20 is formed by binding a plurality of fibers. The fiber yarn bunch 20 is one of a polyacrylonitrile (PAN) fiber, a pitch fiber and other one organic fiber.
A microwave processing step S02: exposing the fiber yam bunch 20 in the microwaving condition to form the oxidation fiber yarn bunch 20A. The microwaving condition comprises: the microwave frequency being 300 MHz through 300,000 MHz; the microwave power being 1 kW/m2 through 1000 kW/m2 ; the operation temperature being 100° C. through 600° C.; the processing time being 1 minute through 40 minutes; and the gas atmosphere being at least one of oxygen, air and ozone.
Furthermore, the oxidation fiber manufacturing method of the present disclosure is implemented in the embodiment which the microwave processing unit 40 is installed with the gas supplying unit 42 for injecting the gas atmosphere into the oven body 33, wherein the gas atmosphere injected into the oven body 33 by the gas supplying unit 42 is at least one of oxygen, air and ozone.
Moreover, the oxidation fiber manufacturing method is implemented in the embodiment that the transmitting unit 30 is installed with the feeding unit 31, the winder unit 32 and the oven body 33, and the microwave processing unit 40 is installed with the magnetron 41 and the gas supplying unit 42, wherein the feeding unit 31 is used to provides the fiber yarn bunch 2, the fiber yarn bunch 20 can pass the oven body 33, the winder unit 32 is used to drag the fiber yarn bunch 20 for continuous transmission, the magnetron 41 is disposed at the oven body 33 for generating the microwave, the gas supplying unit 42 is used to inject the gas with oxygen into the oven body 33, and the winder unit 32, the magnetron 41 and the gas supplying unit 42 are electrically connected to a control unit 50. Operations of the winder unit 32, the magnetron 41 and the gas supplying unit 42 are controlled by the control unit 50, and parameters related to the spinning speed of the winder unit 32, the power of the magnetron 41 and flux of the gas supplying unit 42 are determined according to the property of the processed fiber yarn bunch 20 or the product specification.
the oxidation fiber manufacturing method is implemented in the embodiment that the transmitting unit 30 is installed with the feeding unit 31, the winder unit 32 and the oven body 33, wherein the feeding unit 31 is used to provides the fiber yarn bunch 2, the fiber yarn bunch 20 can pass the oven body 33, the winder unit 32 is used to drag the fiber yarn bunch 20 for continuous transmission, and the transmitting unit 30 is further installed with the thermos unit 34 in the interior of the oven body 33, and as shown in
When the oxidation fiber manufacturing method of the present disclosure is implemented, the transmitting unit 30 as shown in
According to the above possible embodiments associated with the oxidation fiber manufacturing of the present disclosure, the thermos unit 34 can be selected from at least one of a metal oxide, a carbide and a high microwave sensitive material.
When the oxidation fiber manufacturing of the present disclosure is implemented, as shown in
Referring to
Refer to Table 3, and Table 3 is a comparison table showing the measured tensile strengths of the fiber yarn bunches 20, the oxidation fiber yarn bunches 20A and the carbon fiber yarn bunches formed by the next carbonization, wherein several sets of the fiber yarn bunches 20, the oxidation fiber yarn bunches 20A and the carbon fiber yarn bunches are respectively processed by the conventional electro thermal tube heating process and the microwaving processes of the oxidation fiber manufacturing method of the present disclosure. Regarding the conventional electro thermal tube heating process, the processing condition is the oven body temperature of 270° C. and the processing time of 40 minutes, and the obtained results of the physical roperties are called “comparative example 1”. Regarding the microwaving processes of the present disclosure, the processing conditions are the oven body temperature of 220° C., the microwave frequency of 2450 MHz and the processing time of 10 minutes, and the obtained results of the physical properties associated with 24 kW/m2, 22 kW/m2, 16 kW/m2 and 15 kW/m2 microwave powers are called “embodiment 1”, “embodiment 2”, “embodiment 3”, “embodiment 4” and “embodiment 5”. In all of comparative example 1 and embodiments 1 through 5, the fiber yarn bunches 20 are made of polyacrylonitrile. In addition, the cross sections of the oxidation fibers 21 of the oxidation fiber yarn bunches 20A associated with all of the comparative example 1 and the embodiments 1 through 5 are photographed by the scanning electron microscope to obtain the substantial cross section images, and the calculated values that the cross section areas of the oxidation layers 211 respectively divide the cross section areas of the oxidation fibers 21, i.e. the ratios which the oxidation layers 211 occupy the oxidation fibers 21, are also listed in Table 3.
40%
In Table 3, embodiment 5 shows the tensile strength of the final carbon fiber yarn bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the present disclosure is 1.13 times of that in the comparative example 1, and that is the tensile strength has the improvement of 13%. In embodiment 5, the value that the cross section area of the oxidation layer 211 divides the cross section area of the oxidation fiber 21 is 51.2%, i.e. the oxidation layer 211 occupies the 51.2% oxidation fiber 21. Embodiment 4 shows the tensile strength of the final carbon fiber yam bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the present disclosure is 1.17 times of that in the comparative example 1, and that is the tensile strength has the improvement of 17%. In embodiment 4, the value that the cross section area of the oxidation layer 211 divides the cross section area of the oxidation fiber 21 is 61.5%, i.e. the oxidation layer 211 occupies the 61.5% oxidation fiber 21. Embodiment 3 shows the tensile strength of the final carbon fiber yarn bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the present disclosure is 1.23 times of that in the comparative example 1, and that is the tensile strength has the improvement of 23%. In embodiment 3, the value that the cross section area of the oxidation layer 211 divides the cross section area of the oxidation fiber 21 is 82.7%, i.e. the oxidation layer 211 occupies the 82.7% oxidation fiber 21. Embodiment 2 shows the tensile strength of the final carbon fiber yarn bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the present disclosure is 1.27 times of that in the comparative example 1, and that is the tensile strength has the improvement of 27%. In embodiment 2, the value that the cross section area of the oxidation layer 211 divides the cross section area of the oxidation fiber 21 is 91.3%, i.e. the oxidation layer 211 occupies the 91.3% oxidation fiber 21. Embodiment 1 shows the tensile strength of the final carbon fiber yam bunch carbonized by the oxidation fiber yarn bunch processed with the microwaving process of the present disclosure is 1.3 times of that in the comparative example 1, and that is the tensile strength has the improvement of 30%. In embodiment 1, the value that the cross section area of the oxidation layer 211 divides the cross section area of the oxidation fiber 21 is 99.0%, i.e. the oxidation layer 211 occupies the 99.0% oxidation fiber 21.
Thus, the present disclosure further discloses the oxidation fiber 21, and the oxidation fiber 21 comprises an oxidation layer 211 and a core portion 212, wherein the oxidation layer 211 covers the outer side of the core portion 212, and the oxidation layer 211 occupy the more than 50% oxidation fiber 21, or the cross section area of the oxidation layer 211 occupy the more than 50% cross section area of the oxidation fiber 21. As shown in
Certainly, the oxidation fiber 21 of the present disclosure can be formed by using one of the above oxidation fiber manufacturing methods to process the fiber yarn bunch 20. Since the oxidation fiber 21 of the present disclosure is formed under the microwaving condition, the oxidation layer 211 is a microwaved oxidation layer, and the oxidation layer 211 of the oxidation fiber 21 in the oxidation fiber yarn bunch 20A occupies the at least 50% oxidation fiber 21.
When the present disclosure is implemented, the fiber yarn bunch 20 can be one of polyacrylonitrile, pitch and other organic fibers. Certainly, after the microwave focusing process of 24 kW/m2 microwave power is applied on the fiber yarn bunch 20 for 10 minutes to obtain the oxidation fiber, the oxidation layer 211 occupy the 99.0% oxidation fiber 21, or the cross section area of the oxidation layer 211 occupy the 99.0% cross section area of the oxidation fiber 21.
Compared to the prior art, the oxidization fiber manufacturing method disclosed by the present disclosure mainly uses the microwave processing unit to focus the microwave to apply the ultra-fast pre-oxidization process on the fiber yarn bunch, so as to process the fiber yam bunch to form the oxidation fiber. Thus, not only the oxidization time of the oxidation fiber is reduced, but also the oxidation layer in the oxidation fiber processed by the microwaving and oxidizing process occupies more than 50% of the cross section area of the oxidation fiber to efficiently reduce shell-core structure of the oxidation fiber. Even, no obvious shell-core structure exists in the oxidation fiber. Accordingly, relatively positive and reliable means for increasing the performance of carbon fiber are provided.
The above-mentioned descriptions represent merely the exemplary embodiment of the present disclosure, without any intention to limit the scope of the present disclosure thereto. Various equivalent changes, alternations or modifications based on the claims of present disclosure are all consequently viewed as being embraced by the scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 107103128 | Jan 2018 | TW | national |
