TW201932652A - Oxidation fiber manufacturing method - Google Patents

Abstract

The present disclosure mainly uses a transmitting unit to drive the fiber yarn bunch to pass an operation region of the microwave processing unit, and the microwave is focused to perform an ultra-fast pre-oxidization process on the passed fiber yarn bunch, thus processing the fiber yarn bunch to form an oxidation fiber yarn bunch. Not only an oxidization time of an oxidation fiber can be reduced, but also the cross section area of the oxidation layer of the oxidation fiber in the oxidation fiber yarn bunch generated by the microwave focusing oxidization process occupies more than 50% of the cross section area of the oxidation fiber in the oxidation fiber yarn bunch. Thus, the shell-core structure of the oxidation fiber can be reduced efficiently. Even, the oxidation fiber has no obvious shell-core structure. Accordingly, relatively positive and reliable means for increasing the performance of carbon fiber are provided.

Description

Method for producing oxidized fiber and oxidized fiber

The present invention relates to the pre-oxidation technology of carbon fibers, and mainly discloses a method for manufacturing oxidized fibers that helps to improve the performance of carbon fibers, and related oxidized fibers.

Carbon fiber is a new type of carbon material with a carbon content of more than 90% converted from organic fibers after a series of heat treatments. It has high specific strength, high specific modulus, high electrical and thermal conductivity, low thermal expansion coefficient, low density, A series of excellent properties such as high temperature resistance, fatigue resistance, creep resistance, and self-lubrication. It is an ideal functional material and structural material. It is widely used in aerospace, civil aviation and transportation, and has broad application prospects.

Polyacrylonitrile (PAN) as raw fiber carbon fiber preparation process includes polymerization, spinning, pre-oxidation, and carbonization. The pre-oxidation process is the key stage of structural transformation in the preparation of carbon fibers, and it is also the most time-consuming process in heat treatment. At the stage, the purpose is to transform the linear macromolecular chain of polyacrylonitrile into oxidized fiber with heat-resistant structure, so that it will not melt and burn during subsequent carbonization, and can maintain the fiber morphology.

The structural transformation of the precursor fiber during the pre-oxidation process largely determines the structure and performance of the carbon fiber. In industrial production, most systems use a pre-oxidation method with gradient heating. In this process, a suitable temperature gradient range is necessary. If the starting temperature is too low, it does not contribute to the pre-oxidation process and takes time and costs, but the starting temperature is too high, and the severe reaction exotherm will cause the PAN macromolecular chain without heat resistance to fuse; in addition, if the ending temperature is too high, the concentration Exothermic heat will destroy the structure of pre-oxygenated filaments and cause excessive pre-oxidation, which is not conducive to the preparation of high-strength carbon fibers, but the termination temperature is too low, and the pre-filament may not be fully pre-oxidized.

Furthermore, when the pre-oxidation reaction is carried out by heating, as the pre-oxidation reaction proceeds, since the heat is transferred from the outer layer of the precursor to the inner layer, an oxide layer with a dense trapezoidal structure is first formed on the outer layer of the precursor ( Leather part), which instead hinders the diffusion of oxygen to the core of the inner layer of the raw silk, causing one of the fibers 11 in one of the oxidized fibers 10 as shown in FIG. 1 to produce an oxidized oxide layer 111 (skin part) and A core-core structure of a core portion 112 is obviously different. A skin-core interface 113 exists between the oxide layer 111 and the core portion 112. The inspection of the sheath-core structure uses a scanning electron microscope (SEM) to take a solid image to observe the cross-section of the oxidized fiber and calculate the cross-sectional area of the oxide layer and the cross-sectional area of the core and The cross-sectional area of the oxidized fiber and the degree of the sheath-core structure are determined by the core ratio (%) equal to the cross-sectional area of the core divided by the sum of the cross-sectional area of the oxide layer and the cross-sectional area of the core. That is, the core ratio (%) is equal to the cross-sectional area of the core divided by the cross-sectional area of the oxidized fiber. In addition, the physical properties of the oxidized fiber 10 and the carbon fiber made by it, such as tensile strength and tensile modulus, also depend on the degree of oxidation and cyclization of the oxidized fiber 10 or the oxide layer 111; the oxidized fiber 10 or The higher the degree of oxidation and cyclization of the oxide layer 111, the higher the tensile strength and tensile modulus of the carbon fiber made from the oxidized fiber 10. The oxide layer 111 is in an oxidized state, so the structure is dense and leads to high tensile strength and high tensile modulus of the manufactured carbon fiber. The core 112 is in an incompletely oxidized or unoxidized state, so the structure is loose and results in The carbon fiber has low tensile strength and low tensile modulus. Therefore, the skin-core structure caused by the inconsistent oxidation between the oxide layer 111 and the core portion 112 is one of the main reasons for the reduction of the tensile strength of the carbon fiber. Therefore, how to shorten the pre-oxidation time during the pre-oxidation reaction, and how to increase the degree of pre-oxidation while reducing or even eliminating the skin-core structure, has a significant impact on the reduction of carbon fiber production costs and the improvement of properties (tensile strength and tensile modulus). Significance.

In view of this, the present invention is to provide a method for manufacturing oxidized fibers that can effectively shorten the oxidation time of oxidized fibers, and effectively reduce the skin-core structure of oxidized fibers, and even allow the oxidized fibers to have no apparent core-core structure, and the related oxidation. Fiber for its main purpose.

The oxidized fiber manufacturing method of the present invention is suitable for pre-oxidizing a fiber yarn bundle into an oxidized fiber yarn bundle, the fiber yarn bundle is composed of a fiber or a plurality of the fibers assembled into a bundle, and the oxidized fiber yarn bundle is composed of An oxidized fiber or a plurality of the oxidized fibers are assembled into a bundle, and the method for manufacturing the oxidized fibers includes the following steps: a yarn bundle providing step: preparing the fiber yarn bundle; a microwave processing step: exposing the fiber yarn bundle to a microwave The condition becomes this oxidized fiber yarn bundle.

In an embodiment, the method for manufacturing oxidized fibers of the present invention is suitable for pre-oxidizing the fiber yarn bundle into the oxidized fiber yarn bundle, and the fiber yarn bundle is composed of one fiber or a plurality of the fibers assembled into a bundle The oxidized fiber yarn bundle is composed of the oxidized fiber or a plurality of the oxidized fibers assembled into a bundle. The method for manufacturing the oxidized fiber includes the following steps: a. Providing a transmission unit and a microwave processing unit; b. Providing the fiber Yarn bundles, and the fiber yarn bundles are placed on the transfer unit, and the transfer unit can drive the fiber yarn bundles through the microwave processing unit; c. Start the microwave processing unit, the microwave conditions are generated by the microwave processing unit; d. starting the transmission unit, driving the fiber yarn bundle under the microwave condition for a processing time by the transmission unit, so that the fiber yarn bundle becomes the oxidized fiber yarn bundle.

According to the method for manufacturing an oxidized fiber, the fibers of the fiber yarn bundle are pre-oxidized into the oxidized fiber by the method for manufacturing an oxidized fiber.

According to the method for manufacturing an oxidized fiber, the microwave conditions include: a microwave frequency, the microwave frequency is between 300 and 300,000 MHz; a microwave power, the microwave power is between 1 and 1000 kW / m ² ; an operating temperature, The working temperature is between 100 ° C and 600 ° C; and, a gas atmosphere is one of oxygen, air, and ozone, or a mixture thereof.

According to the method for manufacturing an oxidized fiber, the processing time is between 1 and 40 minutes.

According to the manufacturing method of the oxidized fiber, the microwave power is between 10 and 24 kW / m ² .

According to the manufacturing method of the oxidized fiber, the microwave frequency is between 2000 and 3000 MHz, the working temperature is between 150 and 350 ° C, and the processing time is between 5 and 20 minutes.

According to the method for manufacturing oxidized fibers, the fiber yarn bundle is one of polyacrylonitrile (PAN) fibers, pitch fibers, or other organic fibers.

According to the manufacturing method of the oxidized fiber, the conveying unit is provided with a feeding unit for providing the fiber yarn bundle, a winding unit for continuously transmitting the fiber yarn bundle, and a furnace body for passing the fiber yarn bundle; the microwave The processing unit is provided with a magnetron for generating the microwave frequency and the microwave power in the furnace body, and a gas supply unit for introducing the gas atmosphere into the furnace body.

According to the method for manufacturing an oxidized fiber, the winding unit, the magnetron, and the gas supply unit are electrically connected to a control unit.

According to the manufacturing method of the oxidized fiber, a heat preservation unit is provided inside the furnace body.

According to the manufacturing method of the oxidized fiber, the heat preservation unit is one or a combination of metal oxides, carbides, and microwave high-sensitivity materials.

According to the manufacturing method of the oxidized fiber, the fiber yarn bundle is continuously received by the microwave processing unit in a stacking manner in the furnace body.

In the oxidized fiber of the present invention, the oxidized fiber includes at least an oxidized layer and a core portion, the oxidized layer is coated on the outer side of the core portion, and the cross-sectional area of the oxidized layer accounts for at least the cross-sectional area of the oxidized fiber. above 50. Wherein, the oxidized fiber is made by exposing the fiber to the microwave condition. Preferably, the oxidized fiber is made of an organic fiber exposed to the microwave condition.

According to the above structural features, the cross-sectional area of the oxide layer accounts for at least 60% of the cross-sectional area of the oxidized fiber.

According to the above structural features, the cross-sectional area of the oxide layer accounts for at least 80% of the cross-sectional area of the oxidized fiber.

According to the above structural features, the cross-sectional area of the oxide layer accounts for at least 90% of the cross-sectional area of the oxidized fiber.

According to the above structural features, the cross-sectional area of the oxide layer accounts for at least 99% of the cross-sectional area of the oxidized fiber.

The oxidized fiber manufacturing method disclosed in the present invention mainly uses the microwave focusing of a microwave processing unit to apply ultra-high-speed pre-oxidation treatment to fiber yarn bundles to process the fiber yarn bundles into oxidized fibers, which can not only effectively reduce the oxidation time of oxidized fibers, but also The oxidized layer in the oxidized fiber accounts for at least 50% of the cross-sectional area of the oxidized fiber, which effectively reduces the skin-core structure of the oxidized fiber; when the oxidized layer in the oxidized fiber accounts for at least 80% of the cross-sectional area of the oxidized fiber , Can even make the oxidized fiber reach no obvious skin-core structure. Therefore, the present invention improves carbon fiber performance by a relatively more active and reliable means.

The invention mainly provides a method for manufacturing oxidized fibers which can effectively shorten the oxidation time of oxidized fibers, effectively reduce the structure of the oxidized fibers, and even make the oxidized fibers have no obvious core-core structure, and related oxidized fibers. As shown in FIG. 2 and FIG. 3, the method for manufacturing an oxidized fiber of the present invention basically includes the following steps:

a. Provide a transfer unit 30 and a microwave processing unit 40; In implementation, the transfer unit 30 is provided with a feeding unit 31 that provides a fiber yarn bundle 20, and a winding tow the continuous transmission of the fiber yarn bundle 20 Unit 32, a furnace body 33 through which the fiber yarn bundle 20 passes, wherein the fiber yarn bundle 20 may be composed of a fiber (not shown) or a plurality of the fibers assembled into a bundle; the microwave processing unit 40 is connected to The furnace body 33 is provided with at least one magnetron 41 for generating microwaves, and a gas supply unit 42 for passing oxygen-containing gas into the furnace body 33. The gas supply unit 42 is connected to an air inlet 331 of the furnace body 33. An oxygen-containing system enters the furnace body 33 through the air inlet 331 and is discharged from an air outlet 332 of the furnace body 33. The conveying unit 30 is further provided with a heat preservation unit 34 inside the furnace body 33. Preferably, the microwave processing unit 40 is provided with a plurality of the magnetrons 41 at the furnace body 33; the plurality of the magnetrons 41 are arranged oppositely or offset from each other at the upper and lower sides of the furnace body 33, or The plurality of magnetrons 41 are disposed on one side (upper or lower side) of the furnace body 33. As shown in FIG. 3, the plurality of magnetrons 41 are disposed on the upper and lower sides of the furnace body 33 and are opposed to each other. Arrangement. Optimally, as shown in FIG. 3, the plurality of magnetrons 41 are arranged opposite to each other, so that the upper half and the lower half of the fiber yarn bundle 20 passing through the furnace body 33 can be uniformly uniformed at the same time. The microwave irradiation treatment can shorten the length of the furnace body 33 and thus shorten the process time and speed up the production.

b. Provide the fiber yarn bundle 20 and place the fiber yarn bundle 20 on the transfer unit 30, and enable the transfer unit 30 to drive the fiber yarn bundle 20 through the microwave processing unit 40. For example, the rolled fiber bundle 20 is installed at the transfer unit 30 in a type that can be driven by the transfer unit 30 to continuously pass through the working area of the microwave processing unit 40. In the embodiment, the fiber is rolled into the roll The yarn bundle 20 is placed in the feeding unit 31, and the trailing end of the fiber yarn bundle 20 is guided through the furnace body 33 and fixed to the winding unit 32. The fiber yarn bundle 20 may be polyacrylonitrile ( PAN), pitch, or other organic fibers.

c. Start the microwave processing unit 40, and a microwave condition is generated by the microwave processing unit 40. The microwave condition includes: a microwave frequency, the microwave frequency is between 300 and 300,000 MHz; a microwave power, the microwave power is between 1 ~ 1000 kW / m ² ; an operating temperature, which is between 100 ~ 600 ℃; and, a gas atmosphere, which is one or a mixture of oxygen, air, and ozone, and the gas atmosphere is the foregoing Of oxygen-containing gas. In this embodiment, the gas-supplying unit 42 is used to pass oxygen-containing gas into the furnace body 33 at the same time.

d. Start the transmitting unit 30, and drive the fiber yarn bundle 20 under the microwave condition for a processing time by the transmitting unit 30, so that the fiber yarn bundle 20 becomes the oxidized fiber yarn bundle 20A. For example, the transmission unit 30 drives the fiber yarn bundle 20 to continuously receive microwave focusing processing at a speed of 1 to 40 minutes through the working area of the microwave processing unit 40 to become an oxidized fiber yarn bundle 20A. The processing time is between 1 to 40 minutes. In this embodiment, the fiber yarn bundle 20 is driven by the conveying unit 30 to continuously receive the microwave focusing treatment of the microwave processing unit 40 for a speed of 1 to 40 minutes through the furnace body 33 to become the oxidized fiber yarn bundle 20A. In addition, the fiber yarn bundle 20 can continuously receive the microwave focusing treatment of the microwave processing unit 40 in the furnace body 33 in a stacking manner at a speed of 1 to 40 minutes through the furnace body 33 to become the oxidized fiber yarn bundle 20A. For example, the fiber yarn bundle 20 enters the furnace body 33 at the front end of the furnace body 33 and is transferred to the rear end of the furnace body 33, and then is transferred from the rear end of the furnace body 33 to the front end of the furnace body 33. Then, it is transferred from the front end of the furnace body 33 to the rear end of the furnace body 33 again. In this way, the winding is repeated until it is transferred from the rear end of the furnace body 33 as the oxidized fiber yarn bundle 20A as required. . The use of the stacked winding method can effectively shorten the required length of the furnace body 33.

According to the method of manufacturing the oxidized fiber of the present invention, under the operation of the conveying unit 30, the fiber yarn bundle 20 can be driven through the working area of the microwave processing unit 40 at a preset speed, and the fiber yarn bundle 20 can pass through the working area. During the working area of the microwave processing unit 40, the fiber yarn bundle 20 continuously passing through the furnace body 33 is subjected to ultra-high-speed pre-oxidation treatment using microwave focusing, and the fiber yarn bundle 20 is processed into the oxidized fiber yarn bundle 20A. Please also refer to FIG. 4 at the same time, the fiber yarn bundle 20 is composed of the fiber or a plurality of the fibers, and the oxidized fiber yarn bundle 20A is composed of the oxidized fiber 21 or a plurality of the oxidized fibers 21 Composed of bundles, the oxidized fiber manufacturing method is to pre-oxidize the fibers of the fiber yarn bundle 20 into the oxidized fibers 21 by the oxidized fiber manufacturing method.

Please refer to FIG. 4 at the same time. The method for manufacturing the oxidized fiber of the present invention is implemented without microwave, microwave power 12kW / m ² , microwave power 16 kW / m ² , microwave power 20 kW / m ² , and microwave power 24 kW /. The microwave focusing treatment of m ² is applied to the fiber bundle 20, and the microwave focusing treatment with a microwave power of 24 kW / m ² can be surely obtained. After 10 minutes, the fiber bundle 20A of the oxidized fiber can be obtained. The oxidation degree of the oxidized fiber 21 reaches 100%. Corresponding to the fiber yarn bundle 20, the oxidized fiber yarn bundle 20A is composed of a single of the oxidized fiber 21 or a plurality of the oxidized fiber 21 gathered into a bundle. Similarly, after the microwave fiber treatment with microwave power of 20 kW / m ² is focused on the fiber yarn bundle 20 for 15 minutes, the oxidation degree of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A can reach 100%; After the microwave focusing treatment with a power of 16 kW / m ² is applied to the fiber bundle 20 for 25 minutes, the oxidation degree of the oxidized fiber 21 in the oxidized fiber bundle 20A can reach 100%. And even if only the microwave focusing treatment with a microwave power of 12 kW / m ² is applied to the fiber bundle 20 after 40 minutes, even if the oxidized fiber 21 in the oxidized fiber bundle 20A cannot be oxidized to 100%, but The degree of oxidation of the oxidized fiber 21 can be 89%. If only the traditional heating process is used to heat the fiber yarn bundle 20 at 270 ° C for 40 minutes without a microwave process, the oxidation degree of the oxidized fiber 21 is only 70% at most. Therefore, compared with the traditional heating process, the microwave process provided by the oxidized fiber manufacturing method of the present invention can effectively increase the oxidation degree of the oxidized fiber 21 and shorten the process time, especially with a microwave power of 24 kW / m ² . Microwave focusing treatment is performed on the fiber bundle 20 for 10 minutes to achieve the 100% oxidation degree of the oxidized fiber 21, which is the optimal process condition for the oxidation stage.

At the same time, please refer to Figure 5 to treat the fiber yarn bundle 20 with microwave power of 24 kW / m ² with microwave focusing, and process them for 2 minutes, 4 minutes, 5 minutes, 10 minutes, and 15 minutes, and inspect the formed ones. The degree of cyclization of the oxidized fiber 21, the degree of cyclization of the oxidized fiber 21 after 5 minutes reaches 100%, so the time required for the degree of cyclization to reach 100% 5 minutes is less than the time required for the degree of oxidation 10 minutes. Please refer to FIG. 6, FIG. 7, and FIG. 8 at the same time, and respectively apply the microwave oxidizing fiber manufacturing method of the present invention to the fiber bundle 20 with a microwave focusing treatment of 24 kW / m ² for 5 minutes, 10 minutes, and A section image of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A manufactured in 15 minutes was taken with a scanning electron microscope (SEM), and it was found that the oxidized layer 211 occupied the oxidized fiber 21 More than 99.0% or the cross-sectional area of the oxide layer 211 accounts for 99.0% or more of the cross-sectional area of the oxidized fiber 21, and there is no obvious skin-core structure.

Please refer to Tables 1 and 2 at the same time. Table 1 is the traditional process of heating by electric heating tube and the microwave process using the oxidized fiber manufacturing method of the present invention. The fiber bundle 20 and the oxidized fiber bundle 20A are measured. A comparison table of the tensile strength of carbon fiber yarn bundles made from carbonization and its subsequent carbonization; Table 2 shows the traditional process of electric tube heating and the microwave process using the oxidized fiber manufacturing method of the present invention. Comparison table of tensile modulus of oxidized fiber tow 20A and carbon fiber tow made from subsequent carbonization. In the aforementioned traditional manufacturing process using electric heating tube heating, the process conditions are that the furnace temperature is 270 ° C and the processing time is 40 minutes. The obtained physical property results are listed as "Comparative Example 1"; the microwave of the aforementioned oxidized fiber manufacturing method of the present invention The process conditions are as follows: the temperature of the furnace body is 220 ° C, the microwave frequency is 2450 MHz, the microwave power is 24 kW / m ² , and the processing time is 10 minutes. The physical property results obtained are listed in "Example 1". The fiber bundle 20 in Comparative Example 1 and Example 1 was made of polyacrylonitrile.

Table I: Table 1 shows that the tensile strength of the oxidized fiber yarn bundle produced in the microwave process of the oxidized fiber manufacturing method of the first embodiment after the final carbonization is 1.3 times that of Comparative Example 1 (except 3675) With 2824), that is, the tensile strength is increased by 30%. Because the microwave process can make the PAN oxidation more complete, the strength of the oxidized fiber yarn bundle in the microwave process is slightly lower than the strength of the oxidized fiber yarn bundle in the traditional electric heating control process. This is the microwave process of the oxidized fiber manufacturing method of the present invention. Another evidence for increasing the degree of oxidation of the fiber tow.

Table II: Table 2 shows that the tensile modulus of the oxidized fiber yarn bundle produced by the microwave process of the oxidized fiber manufacturing method of the present invention in Example 1 after the final carbonization is 1.17 times (227.1) Divide by 194.4), which means that the tensile modulus is increased by 17%.

So far, compared with the oxidized fiber yarn bundle which acts on the fiber yarn bundle by the traditional heating process, the present invention shortens the 40 minutes required by the traditional heating process to 10 minutes, so the process efficiency is increased by 3 times, and the process time is saved; Compared with the traditional heating process, the present invention also increases the tensile strength of carbon fiber yarn bundles by 30% and the tensile modulus by 17%. Compared with the traditional heating process, the present invention also includes the same among the oxidized fiber yarn bundles 20A. The cross-sectional area of the oxide layer 211 of the oxidized fiber 21 accounts for 99.0% or more of the cross-sectional area of the oxidized fiber 21, so that it has no obvious skin-core structure, so that the cross-section of the oxidized fiber yarn bundle 20A tends to be more uniform. Therefore, the tensile strength and tensile modulus of the carbon fiber yarn bundle can be improved. Therefore, the present invention can improve the carbon fiber performance by a relatively more active and reliable means.

The oxidized fiber manufacturing method of the present invention is, when implemented, the oxidized fiber manufacturing method is preferably performed with a microwave focusing treatment of 24 kW / m ² on the fiber bundles for 5 to 10 minutes. Of course, during the implementation of the oxidized fiber manufacturing method of the present invention, the oxidized fiber manufacturing method can also be applied to these fiber yarn bundles with a microwave focusing of 24 kW / m ² for 5 to 10 minutes; As shown in the figure, the conveying unit 30 is provided with the feeding unit 31 for providing the fiber yarn bundle 20, the winding unit 32 for continuously conveying the fiber yarn bundle 20, and the furnace body through which the fiber yarn bundle 20 passes. 33; The microwave processing unit 40 is an implementation example of the magnetron 41 provided at the furnace body 33 for generating microwaves, and the gas supply unit 42 provided for passing oxygen-containing gas into the furnace body 33 State presentation. The oxidized fiber manufacturing method of the present invention is applicable to the continuous production of carbon fiber yarn bundles after the fiber yarn bundles 20 pass through the furnace body 33 without being taken up by the winder unit 32. The production mode of winding the fiber yarn bundle 20 is rolled out by the feeding unit 31 and taken up by the winding unit 32.

Of course, the oxidized fiber manufacturing method of the present invention can also be applied to a batch production method. In the embodiment of the batch production method, the following steps can be performed sequentially. As shown in FIG. 9, the oxidized fiber manufacturing method of the present invention is suitable for pre-oxidizing the fiber tow 20A to the oxidized fiber tow 20A:

A step S01 of providing a yarn bundle: preparing the fiber yarn bundle 20, the fiber yarn bundle 20 may be composed of a single fiber or a plurality of the fibers assembled into a bundle; the fiber yarn bundle 20 may be polyacrylonitrile (PAN) Fiber, pitch fiber or other organic fibers;

A microwave processing step S02: exposing the fiber yarn bundle 20 to the microwave condition, the microwave condition includes: the microwave frequency, the microwave frequency is between 300 and 300,000 MHz; the microwave power, the microwave power is between 1 ~ 1000 kW / m ² ; the working temperature, the working temperature is between 100 ~ 600 ° C; the processing time, the processing time is between 1 ~ 40 minutes; and, the gas atmosphere, the gas atmosphere is oxygen, air One or a combination of ozone.

Furthermore, in the method for manufacturing an oxidized fiber according to the present invention, in the case where the microwave processing unit 40 is provided with the gas supply unit 42 for passing oxygen-containing gas into the furnace body 33, the gas supply unit 42 is passed into the The oxygen-containing gas in the furnace body 33 may be one of oxygen, air, and ozone, or a mixture thereof.

And, in the oxidized fiber manufacturing method of the present invention, the feeding unit 30 is provided with the feeding unit 31 for providing the fiber yarn bundle 20, the winding unit 32 for continuously transporting the fiber yarn bundles 20, and the fiber The furnace body 33 through which the yarn bundle 20 passes; the microwave processing unit 40 is provided at the furnace body 33 with the magnetron 41 for generating microwaves, and a furnace for passing oxygen-containing gas into the furnace body 33 In the implementation mode of the gas supply unit 42, the winding unit 32, the magnetron 41 and the gas supply unit 42 can be electrically connected to a control unit 50. The control unit 50 can control the operation of the winding unit 32, the magnetron 41 and the air supply unit 42, and can set the rotation speed of the winding unit 32 according to the characteristics of the fiber bundle 20 processed or the product specifications. The operating parameters such as the power of the magnetron 41 and the flow of the gas supply unit 42.

In the oxidized fiber manufacturing method of the present invention, the feeding unit 31 is provided in the conveying unit 30 to provide the fiber yarn bundle 20, the winding unit 32 to continuously convey the fiber yarn bundle 20, and the fiber yarn bundle 20 is provided. In the adopted embodiment of the furnace body 33, the conveying unit 30 can further include the thermal insulation unit 34 inside the furnace body 33. As shown in FIG. 10, the thermal storage effect of the thermal insulation unit 34 can be used to make The interior of the furnace body 33 is maintained at a preset working temperature, and the purpose of saving energy is achieved. In FIG. 10, the feeding unit 31 provides a plurality of the fiber yarn bundles 20 arranged in parallel with each other to enter the furnace body 33.

During the implementation of the oxidized fiber manufacturing method of the present invention, as shown in FIG. 3, the conveying unit 30 may be provided inside the furnace body 33 at positions above and below the conveying path of the fiber yarn bundle 20, respectively. The heat preservation unit 34; or as shown in FIG. 10, the heat preservation unit 34 surrounding the conveying path of the fiber yarn bundle 20 is provided inside the furnace body 33, so that the fiber yarn bundle 20 is uniformly heated.

In the oxidized fiber manufacturing method of the present invention, the thermal insulation unit 34 can be selected from one or a combination of metal oxides, carbides, and microwave high-sensitivity materials in various possible implementation modes.

In implementing the oxidized fiber manufacturing method of the present invention, as shown in FIG. 3, the microwave processing unit 40 may be provided with the magnetic control at positions above and below the transmission path of the fiber bundle 20, respectively. Tube 41; or the microwave processing unit 40 is provided with a plurality of magnetrons 41 surrounding the transmission path of the fiber yarn bundle 20, so that the fiber yarn bundle 20 can be uniformly subjected to microwave focusing processing.

Please refer to FIG. 4 again. As mentioned above, after the microwave focusing treatment with a microwave power of 12 kW / m ² is performed at 220 ° C. for 40 minutes, the oxidation degree of the oxidized fiber 21 reaches 89%. In the traditional heating process, the fiber bundle 20 is heated at 270 ° C for 40 minutes without a microwave process, and the oxidation degree of the oxidized fiber 21 reaches 70%. Therefore, compared with the traditional heating process, the oxidized fiber manufacturing method of the present invention can achieve a higher degree of oxidation at a lower temperature, so that waste of thermal energy can be avoided.

Please refer to Table 3 at the same time. Table 3 is the traditional process of heating by electric heating tube and the microwave process using the oxidized fiber manufacturing method of the present invention. The fiber yarn bundle 20, the oxidized fiber yarn bundle 20A and subsequent Comparison table of tensile strength of carbon fiber tow made from carbonization. In the aforementioned traditional manufacturing process using electric heating tube heating, the process conditions are that the furnace temperature is 270 ° C and the processing time is 40 minutes. The obtained physical property results are listed as "Comparative Example 1"; the microwave of the aforementioned oxidized fiber manufacturing method of the present invention The process conditions are as follows: the furnace temperature is 220 ° C, the microwave frequency is 2450 MHz, and the processing time is 40 minutes. When the microwave power is 22kW / m ² , the physical property results are listed as "Example 2" and when the microwave power is 20 property results kW / m ² the results listed as the "third embodiment", when the object of the results microwave power of 16kW / m ² the results listed as the "fourth embodiment", when the microwave power is 15 kW / m the results of the ² The physical property results are listed as "Example 5". The fiber yarn bundle 20 in Comparative Example 1 and all the examples is made of polyacrylonitrile. In addition, the cross-section of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A of Comparative Example 1 and each example was taken with a scanning electron microscope (SEM, Scanning Electron Microscope), and the oxide layer was calculated. The cross-sectional area of 211 divided by the cross-sectional area of the oxidized fiber 21, that is, the ratio of the oxidized layer 211 to the oxidized fiber 21 is shown in Table 3.

Table three: Table 3 shows that the tensile strength of the oxidized fiber yarn bundle made in the microwave process of the oxidized fiber manufacturing method according to the fifth embodiment after the final carbonization is 1.13 times that of Comparative Example 1, that is, The tensile strength is increased by 13%, and the cross-sectional area of the oxide layer 211 divided by the cross-sectional area of the oxidized fiber 21 is 51.2%, that is, the oxide layer 211 accounts for 51.2% of the oxidized fiber 21; The tensile strength of the oxidized fiber yarn bundle produced by the microwave process of the invented oxidized fiber manufacturing method is 1.17 times that of the carbonized carbon fiber yarn bundle after the final carbonization, that is, the tensile strength is increased by 17%. The cross-sectional area of 211 divided by the cross-sectional area of the oxidized fiber 21 is 61.5%, that is, the oxidized layer 211 occupies 61.5% of the oxidized fiber 21; the third embodiment is a microwave manufacturing process using the oxidized fiber manufacturing method of the present invention. The tensile strength of the finished oxidized fiber yarn bundle is 1.23 times that of Comparative Example 1 after carbonization, that is, the tensile strength is increased by 23%. The cross-sectional area of the oxide layer 211 is divided by the oxidized fiber. The cross-sectional area of 21 is 82.7% That is, the oxidized layer 211 accounts for 82.7% of the oxidized fiber 21. The tensile strength of the oxidized fiber tow made in the microwave process of the oxidized fiber manufacturing method of the second embodiment is the carbon fiber tow It is 1.27 times of Comparative Example 1, that is, the tensile strength is increased by 27%. The cross-sectional area of the oxide layer 211 divided by the cross-sectional area of the oxidized fiber 21 is 91.3%, that is, the oxidized layer 211 occupies the oxidized fiber. 91.3% of 21; Example 1 The tensile strength of the oxidized fiber yarn bundle produced by the microwave process of the oxidized fiber manufacturing method of the present invention after the final carbonization is 1.3 times that of Comparative Example 1, that is, The tensile strength is increased by 30%. The cross-sectional area of the oxide layer 211 divided by the cross-sectional area of the oxidized fiber 21 is 99.0%, that is, the oxide layer 211 accounts for 99.0% of the oxidized fiber 21.

Therefore, the present invention further discloses the oxidized fiber 21, which includes an oxidized layer 211 and a core portion 212. The oxidized layer 211 covers the outer side of the core portion 212, wherein the oxidized layer 211 occupies the oxidized layer. At least 50% or more of the fiber 21 or the cross-sectional area of the oxide layer 211 accounts for at least 50% or more of the cross-sectional area of the oxidized fiber 21. As shown in FIG. 11, the oxide layer 211 occupies at least 80% or more of the oxidized fiber 21, or the cross-sectional area of the oxidized layer 211 occupies at least 80% or more of the cross-sectional area of the oxidized fiber 21.

Of course, the oxidized fiber 21 disclosed in the present invention can be manufactured by the fiber tow 20 using any one of the possible oxidized fiber manufacturing methods of the present invention. Since the oxidized layer 211 is formed under the microwave condition, The oxidized layer 211 is a microwave oxidized layer, and the oxidized layer 211 of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A accounts for at least 50% of the oxidized fiber 21.

During implementation, the fiber yarn bundle 20 may be one of polyacrylonitrile (PAN), pitch, or other organic fibers. Of course, after the oxidized fiber is subjected to a microwave action of 24 kW / m ² on the fiber yarn bundle 20 after a 10-minute microwave focusing treatment, the oxidized layer 211 of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A occupies the oxidized fiber 99.0% of 21, or the cross-sectional area of the oxide layer 211 accounts for 99.0% of the cross-sectional area of the oxidized fiber 21.

Compared with the conventional conventional technology, the oxidized fiber manufacturing method disclosed in the present invention mainly uses the microwave focusing of the microwave processing unit to apply ultra-high-speed pre-oxidation treatment to the fiber yarn bundle to process the fiber yarn bundle into an oxidized fiber yarn bundle. Effectively reduce the oxidation time of the oxidized fiber yarn bundle, and the oxidized layer of the oxidized fiber in the oxidized fiber yarn bundle is subjected to microwave focused oxidation treatment, which occupies at least 50% of the cross-sectional area of the oxidized fiber, effectively reducing the oxidized fiber sheath core structure, The oxidized fiber can be made to have no obvious skin-core structure, and the carbon fiber performance can be improved by a more positive and reliable method.

The above-mentioned embodiments are only for explaining the technical ideas and characteristics of the present invention. The purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. When the scope of the patent of the present invention cannot be limited, That is, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention should still be covered by the patent scope of the present invention.

[Prior art]

10‧‧‧oxidized fiber

11‧‧‧ Fiber

111‧‧‧ oxide layer

112‧‧‧ Core

113‧‧‧Skin Core Interface

[this invention]

20‧‧‧ fiber yarn bundle

20A‧‧‧oxidized fiber yarn bundle

21‧‧‧oxidized fiber

211‧‧‧oxide

212‧‧‧Core

30‧‧‧Transfer Unit

31‧‧‧feeding unit

32‧‧‧Rewinding unit

33‧‧‧furnace

331‧‧‧air inlet

332‧‧‧Air outlet

34‧‧‧Insulation unit

40‧‧‧Microwave processing unit

41‧‧‧Magnetron

42‧‧‧Gas supply unit

50‧‧‧control unit

S01‧‧‧Providing yarn bundle steps

S02‧‧‧Microwave processing steps

Figure 1 is a schematic diagram of the structure of a sheath core of a conventional oxidized fiber. Fig. 2 is a basic flowchart of a method for producing oxidized fibers according to the present invention. FIG. 3 is a schematic structural diagram of a transmission unit and a microwave processing unit of the method for manufacturing an oxidized fiber according to the present invention. Figure 4 shows the method for manufacturing oxidized fibers of the present invention, which uses microwave focusing treatments of 12 kW / m2, 16 kW / m2, 20 kW / m2, and 24 kW / m2, respectively, on fiber yarn bundles and traditional heating processes that act on fiber yarn bundles. Graph of oxidation degree of oxidized fiber. Fig. 5 is a graph showing the degree of cyclization of the oxidized fibers in the oxidized fiber manufacturing method of the present invention using a microwave focusing treatment of 24 kW / m2 on the fiber bundle after 2 minutes, 4 minutes, 5 minutes, 10 minutes, and 15 minutes. FIG. 6 is a solid image of an oxidized fiber cross section in an oxidized fiber yarn bundle manufactured by the oxidized fiber manufacturing method of the present invention with a microwave focusing treatment of 24 kW / m2 for 5 minutes in the fiber yarn bundle. Fig. 7 is a solid image of an oxidized fiber cross section in an oxidized fiber yarn bundle manufactured by the oxidized fiber manufacturing method of the present invention with a microwave focusing treatment of 24 kW / m2 for 10 minutes in the fiber yarn bundle. FIG. 8 is a solid image cross-section of an oxidized fiber in an oxidized fiber yarn bundle manufactured by the method for manufacturing an oxidized fiber with a microwave focusing treatment of 24 kW / m2 for 15 minutes in the fiber yarn bundle. Fig. 9 is another flow chart of the method for producing oxidized fibers according to the present invention. Fig. 10 is a schematic structural view of a furnace body for a method for manufacturing oxidized fiber according to the present invention. FIG. 11 is a schematic structural diagram of the oxidized fiber of the present invention.

Claims (23)

An oxidized fiber manufacturing method is suitable for pre-oxidizing a fiber yarn bundle (20) into an oxidized fiber yarn bundle (20A). The fiber yarn bundle (20) is composed of one fiber or a plurality of the fibers. The oxidized fiber tow (20A) is composed of an oxidized fiber (21) or a plurality of oxidized fibers (21), and the method for manufacturing the oxidized fiber includes the following steps: A step of providing a ray (S01): preparation The fiber yarn bundle (20); a microwave processing step (S02): exposing the fiber yarn bundle (20) to a microwave condition and becoming the oxidized fiber yarn bundle (20A). The method for manufacturing oxidized fiber according to claim 1, wherein the microwave condition includes: a microwave frequency, the microwave frequency is between 300 and 300,000 MHz; and a microwave power, the microwave power is between 1 and 1000 kW / m ² ; a working temperature, which is between 100 ~ 600 ° C; a processing time, which is between 1 ~ 40 minutes; and, a gas atmosphere, which is one of oxygen, air, and ozone Or a mixture of them. The method for manufacturing an oxidized fiber according to claim 2, wherein the microwave power is between 10 and 24 kW / m ² . The method for manufacturing oxidized fibers according to claim 2, wherein the microwave frequency is between 2000 and 3000 MHz, the working temperature is between 150 and 350 ° C, and the processing time is between 5 and 20 minutes. The method for manufacturing oxidized fibers according to claim 1, wherein the fiber yarn bundle (20) is one of polyacrylonitrile (PAN) fibers, pitch fibers, or other organic fibers. An oxidized fiber manufacturing method is suitable for pre-oxidizing a fiber yarn bundle (20) into an oxidized fiber yarn bundle (20A). The fiber yarn bundle (20) is composed of one fiber or a plurality of the fibers. The oxidized fiber yarn bundle (20A) is composed of an oxidized fiber (21) or a plurality of oxidized fibers (21) assembled into a bundle. The method for manufacturing the oxidized fiber includes the following steps: a. Providing a transmission unit (30) and A microwave processing unit (40); b. Providing the fiber yarn bundle (20), and placing the fiber yarn bundle (20) on the transfer unit (30), and enabling the transfer unit (30) to drive the fiber yarn The beam (20) passes through the microwave processing unit (40); c. The microwave processing unit (40) is started, a microwave condition is generated by the microwave processing unit (40); d. The transmission unit (30) is started, and the transmission A unit (30) drives the fiber yarn bundle (20) under the microwave condition for a processing time, so that the fiber yarn bundle (20) becomes the oxidized fiber yarn bundle (20A). The method for manufacturing oxidized fibers according to claim 6, wherein the microwave conditions include: a microwave frequency, the microwave frequency is between 300 and 300,000 MHz; and a microwave power, the microwave power is between 1 and 1000 kW / m ² ; an operating temperature, which is between 100 and 600 ° C; and a gas atmosphere, which is one of oxygen, air, ozone or a mixture thereof. The method for manufacturing oxidized fibers according to claim 7, wherein the processing time is between 1 and 40 minutes. The method for manufacturing an oxidized fiber according to claim 7, wherein the microwave power is between 10 and 24 kW / m ² . The method for manufacturing oxidized fibers according to claim 7, wherein the microwave frequency is between 2000 and 3000 MHz, and the operating temperature is between 150 and 350 ° C. The method for producing oxidized fibers according to claim 6, wherein the fiber yarn bundle (20) is one of polyacrylonitrile (PAN) fibers, pitch fibers, or other organic fibers. The method for manufacturing oxidized fibers according to claim 6, wherein the conveying unit (30) is provided with a feeding unit (31) for supplying the fiber yarn bundle (20), A winding unit (32) and a furnace body (33) for passing the fiber yarn bundle (20); the microwave processing unit (40) is provided on the furnace body (33) for generating the microwave frequency and the microwave A magnetron (41) with power, and a gas supply unit (42) provided for passing the gas atmosphere into the furnace body (33). The method for manufacturing oxidized fiber according to claim 12, wherein the winding unit (32), the magnetron (41) and the gas supply unit (42) are electrically connected to a control unit (50). The method for manufacturing oxidized fibers according to claim 12, wherein a heating unit (34) is provided inside the furnace body (33). The method for manufacturing oxidized fibers according to claim 14, wherein the thermal insulation unit (34) is one or a combination of metal oxides, carbides, and microwave high-sensitivity materials. The method for manufacturing oxidized fibers according to claim 12, wherein the fiber yarn bundle (20) is continuously received by the microwave processing unit (40) in a winding manner in the furnace body (33). An oxidized fiber. The oxidized fiber (21) includes at least an oxide layer (211) and a core portion (212). The oxide layer (211) is coated on the outer side of the core portion (212), and the oxide layer (211) The cross-sectional area of) accounts for at least 50% or more of the cross-sectional area of the oxidized fiber (21). The oxidized fiber according to claim 17, wherein the cross-sectional area of the oxidized layer (211) accounts for at least 60% of the cross-sectional area of the oxidized fiber (21). The oxidized fiber according to claim 17, wherein the cross-sectional area of the oxidized layer (211) accounts for at least 80% or more of the cross-sectional area of the oxidized fiber (21). The oxidized fiber according to claim 17, wherein the cross-sectional area of the oxidized layer (211) accounts for at least 90% of the cross-sectional area of the oxidized fiber (21). The oxidized fiber according to claim 17, wherein the cross-sectional area of the oxidized layer (211) accounts for at least 99% of the cross-sectional area of the oxidized fiber (21). The oxidized fiber according to claim 17, wherein the oxidized fiber (21) is made by exposing a fiber to the microwave condition. The oxidized fiber according to claim 22, wherein the oxidized fiber (21) is an organic fiber.