TWI695096B - Oxidized fiber manufacturing method - Google Patents

Abstract

The invention mainly uses a conveying unit to drive the fiber yarn bundle to continuously pass through the working area of a microwave processing unit, and uses the microwave focusing of the microwave processing unit to apply ultra-high-speed pre-oxidation treatment to the fiber yarn bundle passing through to process the fiber yarn bundle into oxidation The fiber can not only effectively reduce the oxidation time of the oxidized fiber, but the oxide layer of the fiber in the oxidized fiber subjected to microwave focused oxidation treatment at least accounts for more than 50% of the cross-sectional area of the oxidized fiber, effectively reducing the skin-core structure of the oxidized fiber, or even The oxidized fiber can achieve no obvious sheath-core structure, and the performance of carbon fiber can be improved in a more positive and reliable way.

Description

Oxidized fiber manufacturing method

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 oxidized fibers related thereto.

Carbon fiber is a new type of carbon material with more than 90% carbon content 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 are ideal functional materials and structural materials. They are widely used in aerospace, civil aviation and transportation, and have broad application prospects.

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

The structural change of the raw silk during the pre-oxidation process largely determines the structure and performance of the carbon fiber. In industrial production, many systems use a pre-oxidation method with a gradient temperature increase. 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, which takes time and increases costs. However, if the starting temperature is too high, the violent reaction exotherm will melt the PAN macromolecular chain without heat resistance; in addition, if the termination temperature is too high, the concentration Exothermic heat will destroy the structure of the pre-oxygen wire and cause excessive pre-oxidation, which is not conducive to the preparation of high-strength carbon fiber, but the termination temperature is too low, and the original silk may not be fully pre-oxidized.

Furthermore, when the pre-oxidation reaction is carried out by heating, as the pre-oxidation reaction progresses, since the heat is transferred from the outer layer of the raw silk to the inner layer, a dense trapezoidal oxide layer will first be formed on the outer layer of the raw yarn ( Skin), which hinders the diffusion of oxygen to the core of the inner layer of the raw silk, resulting in oxidation of one of the fibers 11 of one of the oxidized fibers 10 as shown in FIG. 1 an oxide layer 111 (skin) and unoxidized In a sheath-core structure with a distinct core portion 112, a sheath-core interface 113 exists between the oxide layer 111 and the core portion 112. The inspection of the skin-core structure is to use a scanning electron microscope (SEM, Scanning Electron Microscope) to take a physical 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, the method of determining the degree of the sheath-core structure is that the core ratio (%) is 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 thereof, 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 the degree of cyclization of the oxide layer 111, the higher the tensile strength and tensile modulus of the carbon fiber made of the oxidized fiber 10. The oxide layer 111 is in an oxidized state, so the structure is dense and results in high tensile strength and high tensile modulus of the carbon fiber produced. The core 112 is in an incompletely oxidized or unoxidized state so the structure is loose and results in the manufactured Carbon fiber has a low tensile strength and a low tensile modulus. Therefore, the skin-core structure caused by the inconsistent degree of oxidation of the oxide layer 111 and the core 112 is one of the main reasons for the decrease in 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 core-sheath structure, has a great effect on the reduction of carbon fiber production costs and the improvement of performance (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 sheath-core structure of oxidized fibers, and even allow the oxidized fibers to have no obvious sheath-core structure, and the related oxidation Fiber, for its main purpose.

The method for manufacturing oxidized fiber of the present invention is suitable for preoxidizing 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. 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: One step of providing the yarn bundle: preparing the fiber yarn bundle; A microwave treatment step: expose the fiber yarn bundle to a microwave condition and become the oxidized fiber yarn bundle.

In an embodiment, the method for producing oxidized fibers of the present invention is suitable for preoxidizing the fiber yarn bundle into the oxidized fiber yarn bundle, 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 one oxidized fiber or a plurality of the oxidized fibers assembled into a bundle, and the method of manufacturing the oxidized fiber includes the following steps: a. Provide a transmission unit and a microwave processing unit; b. Provide the fiber yarn bundle, and place the fiber yarn bundle in the transmission unit, and enable the transmission unit to drive the fiber yarn bundle through the microwave processing unit; c start the microwave processing unit, the microwave processing unit generates the microwave conditions; d. Start the conveying unit, and drive the fiber yarn bundle under the microwave condition for a processing time by the conveying unit, so that the fiber yarn bundle becomes the oxidized fiber yarn bundle.

According to the above-mentioned oxidized fiber manufacturing method, the fiber of the fiber bundle is pre-oxidized into the oxidized fiber by the oxidized fiber manufacturing method.

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

According to the above-mentioned method for manufacturing oxidized fibers, the processing time is between 1 and 40 minutes.

According to the above-mentioned method for manufacturing oxidized fibers, the microwave power is between 10 and 24 kW/m ² .

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

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

According to the above-mentioned manufacturing method of oxidized fiber, the conveying unit is provided with a feeding unit that provides the fiber yarn bundle, a winding unit that drags the fiber yarn bundle for continuous transmission, and a furnace body through which the fiber yarn bundle passes; 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 passing the gas atmosphere into the furnace body.

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

According to the above-mentioned method for manufacturing oxidized fibers, a heat preservation unit is provided inside the furnace body.

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

According to the above-mentioned manufacturing method of oxidized fibers, the fiber yarn bundle is continuously irradiated by the microwave processing unit in a stacked manner in the furnace body.

The oxide fiber of the present invention includes at least an oxide layer and a core, the oxide layer is coated on the outside of the core, and the cross-sectional area of the oxide layer accounts for at least the cross-sectional area of the oxide 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 conditions.

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 method for manufacturing oxidized fiber 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 oxidized fiber, which can effectively reduce the oxidation time of the oxidized fiber, and The oxidized layer of the oxidized fiber accounts for at least 50% of the cross-sectional area of the oxidized fiber, effectively reducing the skin-core structure of the oxidized fiber; when the oxidized layer of the oxidized fiber accounts for at least 80% of the cross-sectional area of the oxidized fiber , And even allow the oxidized fiber to reach no obvious sheath-core structure. Therefore, the present invention improves the performance of carbon fiber in a relatively more active and reliable way.

The invention mainly provides an oxidation fiber manufacturing method which can effectively shorten the oxidation time of the oxidation fiber, and effectively reduce the oxidation fiber sheath-core structure, and even allow the oxidation fiber to reach no obvious sheath-core structure, and the related oxidation fiber. As shown in Figures 2 and 3, the method for manufacturing oxidized fibers 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 to provide a fiber yarn bundle 20, a drag the fiber yarn bundle 20 continuous transmission winding 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 introducing 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. The oxygen-containing system enters the furnace body 33 through the air inlet 331 and is discharged through an air outlet 332 of the furnace body 33. The transfer unit 30 can further be 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 magnetrons 41 are arranged on the upper and lower sides of the furnace body 33 in a relative or staggered arrangement, or A plurality of the magnetrons 41 are provided on one side (upper side or lower side) of the furnace body 33. As shown in FIG. 3, a plurality of the magnetrons 41 are provided on the upper and lower sides of the furnace body 33 and are vertically opposed Arrangement. Optimally, as shown in FIG. 3, the plurality of magnetrons 41 are arranged up and down so that the upper half and the lower half of the fiber yarn bundle 20 passing through the furnace body 33 can be evenly and simultaneously The microwave irradiation treatment can shorten the length of the furnace body 33 and thus shorten the process time and increase the production speed.

b. Provide the fiber yarn bundle 20, and place the fiber yarn bundle 20 on the conveying unit 30, and enable the conveying unit 30 to drive the fiber yarn bundle 20 through the microwave processing unit 40. b. For example, the bundle of fiber yarns 20 is installed at the conveyor unit 30 in a form that can be driven by the conveyor unit 30 to continuously pass through the working area of the microwave processing unit 40; in an embodiment, the bundle of fibers The yarn bundle 20 is placed in the feeding unit 31, and the tail 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, a microwave condition is generated by the microwave processing unit 40, the microwave condition includes: a microwave frequency, the microwave frequency is between 300 ~ 300,000MHz; a microwave power, the microwave power is between 1~1000 kW/m ² ; an operating temperature, the operating temperature is between 100~600 ℃; and, a gas atmosphere, the gas atmosphere is one of oxygen, air, ozone or a mixture thereof, the gas atmosphere is the aforementioned Of oxygen-containing gas. In this embodiment, the gas supply unit 42 simultaneously passes the oxygen-containing gas into the furnace body 33.

d. Starting the conveying unit 30, the conveying unit 30 drives the fiber yarn bundle 20 under the microwave condition for a treatment time, so that the fiber yarn bundle 20 becomes the oxidized fiber yarn bundle 20A. For example, the conveying unit 30 drives the fiber yarn bundle 20 to continuously receive the microwave focusing treatment at a speed of 1 to 40 minutes to pass through the microwave processing unit 40 working area to become the oxidized fiber yarn bundle 20A, the processing time is between 1 to 40 minutes. In this embodiment, the conveying unit 30 drives the fiber yarn bundle 20 to continuously receive the microwave focusing treatment of the microwave processing unit 40 for 1 to 40 minutes to pass 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 a stacked manner in the furnace body 33 through the furnace body 33 to become the oxidized fiber yarn bundle 20A at a speed of 1 to 40 minutes. 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 , And then transferred again from the front end of the furnace body 33 to the rear end of the furnace body 33, in this way repeated winding until it is transferred from the rear end of the furnace body 33 as the oxidized fiber yarn bundle 20A . Using the stacked winding system can effectively shorten the required length of the furnace body 33.

Accordingly, the method for manufacturing oxidized fibers of the present invention can drive the fiber yarn bundle 20 to pass through the working area of the microwave processing unit 40 at a predetermined speed under the operation of the conveying unit 30, and pass the fiber yarn bundle 20 through the During the operation 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 as shown, the fiber yarn bundle 20 is composed of the fibers or a plurality of the fibers assembled into a bundle, and the oxidized fiber yarn bundle 20A is composed of the oxidized fibers 21 or a plurality of the oxidized fibers 21 Composed of bundles, the method for producing oxidized fibers pre-oxidizes the fibers of the fiber yarn bundle 20 into the oxidized fibers 21 by the method for producing oxidized fibers.

Please also refer to the fourth figure, the method of manufacturing oxidized fiber of the present invention is implemented with no microwave, microwave power 12kW/m ² , microwave power 16 kW/m ² , microwave power 20 kW/m ² , microwave power 24 kW/ The microwave focusing treatment of m ² on the fiber yarn bundle 20 can surely obtain the microwave focusing treatment with a microwave power of 24 kW/m ² on the fiber yarn bundle 20 after 10 minutes, and then the oxidized fiber yarn bundle 20A The oxidation degree of the oxidized fiber 21 reaches 100%, and the oxidized fiber yarn bundle 20A is composed of a single oxidized fiber 21 or a plurality of oxidized fibers 21 gathered into a bundle corresponding to the fiber yarn bundle 20. Similarly, after 15 minutes of microwave focusing treatment with the microwave power of 20 kW/m ² on the fiber yarn bundle 20, the oxidation degree of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A can reach 100%; The microwave focusing treatment with the power of 16 kW/m ² can make the oxidation degree of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A reach 100% after 25 minutes of the fiber yarn bundle 20. Even if only 40 minutes of microwave focusing treatment with the microwave power of 12 kW/m ² is applied to the fiber yarn bundle 20 after 40 minutes, even if the oxidation degree of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A cannot reach 100%, but The degree of oxidation of the oxidized fiber 21 can reach 89%. If only the conventional heating process is used to heat the fiber yarn bundle 20 at 270°C for a 40-minute microwave-free process, the oxidation degree of the oxidized fiber 21 can only reach 70% at most. Therefore, compared with the conventional heating process, the microwave process proposed by the method for manufacturing oxidized fiber of the present invention can effectively improve 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 of the oxidized fiber 21 on the fiber yarn bundle 20 for 10 minutes to achieve a 100% oxidation degree is the optimal process condition for the oxidation stage.

At the same time, please refer to the figure 5 and focus on the fiber bundle 20 with microwave power of 24 kW/m ² for 2 minutes, 4 minutes, 5 minutes, 10 minutes and 15 minutes, and inspect the resulting 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 also refer to Figure 6, Figure 7 and Figure 8 together, respectively, the method of manufacturing oxidized fiber of the present invention with 24 kW/m ² microwave focusing treatment on the fiber yarn bundle 20 for 5 minutes, 10 minutes and In 15 minutes, the cross-section of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A was taken with a scanning electron microscope (SEM, Scanning Electron Microscope) to take a physical image, and it was found that the oxidized layer 211 occupied the oxidized fiber 21 99.0% or more, 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 sheath-core structure.

Please also refer to Tables 1 and 2 for reference. Table 1 is the traditional process using electric heating tube heating and the microwave process using the oxidized fiber manufacturing method of the present invention. The fiber yarn bundle 20 and the oxidized fiber yarn bundle 20A are measured And the subsequent tensile strength comparison table of carbon fiber yarn bundles made by carbonization; Table 2 is the traditional manufacturing process using electric heating tube heating method and the microwave manufacturing process using the oxidized fiber manufacturing method of the present invention. The fiber yarn bundle 20 and the Comparison table of tensile modulus of oxidized fiber yarn bundle 20A and carbon fiber yarn bundle made by subsequent carbonization. In the above-mentioned conventional process using an electric heating tube, the process conditions are the furnace body temperature of 270°C and the processing time of 40 minutes. The physical properties obtained are listed as “Comparative Example 1”; the microwave of the method for producing oxidized fiber 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 as “Example 1”. The fiber yarn bundle 20 in Comparative Example 1 and Example 1 is made of polyacrylonitrile.

從表一中顯示實施例一運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸強度是比較例一的1.3倍(3675除以2824)，亦即拉伸強度提高30%。微波製程因能讓PAN氧化更為完全，所以微波製程的該氧化纖維紗束強度略低於傳統電熱管製程的該氧化纖維紗束強度，此為本發明的氧化纖維製造方法之微波製程更能夠讓該纖維紗束提高氧化程度之另一證據。Table I:

Table 1 shows that the oxidized fiber yarn bundle produced by the microwave process of the first embodiment of the oxidized fiber manufacturing method of the present invention has a carbon fiber yarn bundle with a tensile strength 1.3 times that of Comparative Example 1 (3675 divided With 2824), that is, the tensile strength is increased by 30%. The microwave process can make the PAN oxidation more complete, so 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 electrothermal control process. This is the microwave process of the oxidized fiber manufacturing method of the present invention. Another piece of evidence that allows the fiber bundle to increase the degree of oxidation.

從表二中顯示實施例一運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸模數是比較例一的1.17倍(227.1除以194.4)，亦即拉伸模數提高17%。Table II:

Table 2 shows that the oxidation modulus of the oxidized fiber yarn bundle made by the microwave process of Example 1 using the method for producing oxidized fiber of the present invention is 1.17 times (227.1) the tensile modulus of the carbon fiber yarn bundle after the final carbonization is 22 (227.1) Divided by 194.4), that is, the tensile modulus increased by 17%.

So far, compared with the oxidized fiber yarn bundle that the traditional heating process acts on the fiber yarn bundle, the present invention reduces the 40 minutes required by the conventional 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 the carbon fiber yarn bundle by 30% and the tensile modulus by 17%; compared with the conventional heating process, the present invention also uses the oxidized fiber yarn bundle 20A The cross-sectional area of the oxide layer 211 of the oxidized fiber 21 accounts for more than 99.0% of the cross-sectional area of the oxidized fiber 21, so that it has no obvious sheath-core structure, making the cross-section of the oxidized fiber yarn bundle 20A 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 performance of carbon fiber in a more positive and reliable way.

The method for producing oxidized fibers of the present invention is preferably implemented by performing a microwave focusing treatment of 24 kW/m ² on these fiber yarn bundles for 5 to 10 minutes. Of course, the manufacturing method of the oxidized fiber of the present invention, when implemented, can also use the method of manufacturing the oxidized fiber with 24 kW/m ² microwave focusing treatment on the fiber yarn bundles for 5 to 10 minutes; and, as the third As shown in the figure, the conveying unit 30 is provided with the feeding unit 31 that provides the fiber yarn bundle 20, the winding unit 32 that drags the fiber yarn bundle 20 for continuous transmission, and the furnace body through which the fiber yarn bundle 20 passes 33; The microwave processing unit 40 is provided with the magnetron 41 for generating microwaves at the furnace body 33, and an embodiment of the gas supply unit 42 for passing oxygen-containing gas into the furnace body 33 Mode of presentation. Therefore, the method for producing oxidized fibers of the present invention can be applied to the fiber yarn bundle 20 after passing through the furnace body 33 without being wound by the winding unit 32 but following the carbonization process to produce carbon fiber yarn bundle in a continuous production mode, or suitable for The production method of winding the fiber yarn bundle 20 by the feeding unit 31 and winding by the winding unit 32.

Of course, the method for manufacturing oxidized fibers of the present invention can also be applied to batch production. In the embodiment of the batch production method, the following steps may be performed in sequence. As shown in FIG. 9, the method for manufacturing oxidized fibers of the present invention is suitable for preoxidizing the fiber yarn bundle 20 into the oxidized fiber yarn bundle 20A:

1. Providing a yarn bundle step S01: 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) One of fiber, pitch fiber or other organic fiber;

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

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

And, in the method for manufacturing oxidized fibers of the present invention, the feeding unit 31 that provides the fiber yarn bundle 20, the winding unit 32 that drags the fiber yarn bundles 20 for continuous transmission, and the fiber The furnace body 33 through which the yarn bundle 20 passes; the microwave processing unit 40 is provided with the magnetron 41 for generating microwaves at the furnace body 33, and the furnace body 33 is provided 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 speed of the winding unit 32 according to the characteristics of the processed fiber yarn bundle 20 or product specifications , The power of the magnetron 41 and the flow rate of the gas supply unit 42 and other operating parameters.

In the method for manufacturing oxidized fiber of the present invention, the feeding unit 31 that provides the fiber yarn bundle 20 is provided in the conveying unit 30, the winding unit 32 that drags the fiber yarn bundle 20 for continuous transmission, and the fiber yarn bundle 20 are provided Under the implementation of the furnace body 33, the conveying unit 30 can further be provided with the heat preservation unit 34 inside the furnace body 33. As shown in FIG. 10, the heat storage effect of the heat preservation unit 34 can be utilized to make The inside 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 fiber yarn bundles 20 arranged parallel to each other to enter the furnace body 33.

According to the method for manufacturing oxidized fiber of the present invention, the conveying unit 30 can be provided at the upper and lower positions of the furnace body 33 relative to the conveying path of the fiber yarn bundle 20 as shown in FIG. 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 manufacturing method of the oxidized fiber of the present invention, under various possible implementations, the heat preservation unit 34 may be selected from one or a combination of metal oxide, carbide, and microwave high-sensitivity material.

According to the method for manufacturing oxidized fibers of the present invention, the microwave processing unit 40 can be provided with the magnetrons at the upper and lower positions relative to the transmission path of the fiber yarn bundle 20 as shown in FIG. The tube 41; or the microwave processing unit 40 is provided with a plurality of magnetrons 41 that surround the transmission path of the fiber yarn bundle 20, so that the fiber yarn bundle 20 is uniformly subjected to microwave focusing treatment.

Please refer to FIG. 4 again. As mentioned above, after the microwave focusing treatment with the microwave power of 12 kW/m ² at 220°C for 40 minutes, the oxidation degree of the oxidized fiber 21 reaches 89%; and In the conventional heating process, the fiber yarn bundle 20 is heated at 270° C. for a 40-minute microwave-free process, and the oxidation degree of the oxidized fiber 21 reaches 70%. Therefore, compared with the conventional heating process, the manufacturing method of the oxidized fiber of the present invention can achieve a higher degree of oxidation at a lower temperature, so that waste of heat energy can be avoided.

Please also refer to Table 3, which is the traditional process using the electric heating tube heating method 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 the subsequent Comparison table of tensile strength of carbon fiber yarn bundle made by carbonization. In the above-mentioned conventional process using an electric heating tube, the process conditions are the furnace body temperature of 270°C and the processing time of 40 minutes. The physical properties obtained are listed as “Comparative Example 1”; the microwave of the method for producing oxidized fiber of the present invention The process conditions are: the furnace temperature is 220°C, the microwave frequency is 2450 MHz, and the processing time is 40 minutes. When the microwave power is 22 kW/m ² , the physical property results are listed as “Example 2”, 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 Five". 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 the various examples is taken with a scanning electron microscope (SEM, Scanning Electron Microscope) to take a physical image, and the oxide layer is calculated The cross-sectional area of 211 divided by the cross-sectional area of the oxidized fiber 21, that is, the ratio of the oxide layer 211 to the oxidized fiber 21, is shown in Table 3.

從表三中顯示實施例五運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸強度是比較例一的1.13倍，亦即拉伸強度提高13%，該氧化層211的斷面面積除以該氧化纖維21之斷面面積係為51.2%，亦即該氧化層211佔該氧化纖維21之51.2%；實施例四運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸強度是比較例一的1.17倍，亦即拉伸強度提高17%，該氧化層211的斷面面積除以該氧化纖維21之斷面面積係為61.5%，亦即該氧化層211佔該氧化纖維21之61.5%；實施例三運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸強度是比較例一的1.23倍，亦即拉伸強度提高23%，該氧化層211的斷面面積除以該氧化纖維21之斷面面積係為82.7%，亦即該氧化層211佔該氧化纖維21之82.7%；實施例二運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸強度是比較例一的1.27倍，亦即拉伸強度提高27%，該氧化層211的斷面面積除以該氧化纖維21之斷面面積係為91.3%，亦即該氧化層211佔該氧化纖維21之91.3%；實施例一運用本發明的氧化纖維製造方法之微波製程所製成之氧化纖維紗束，其最終碳化後之碳纖維紗束的拉伸強度是比較例一的1.3倍，亦即拉伸強度提高30%，該氧化層211的斷面面積除以該氧化纖維21之斷面面積係為99.0%，亦即該氧化層211佔該氧化纖維21之99.0%。Table 3:

From Table 3, it is shown that the tensile strength of the carbon fiber yarn bundle after the final carbonization of the oxidized fiber yarn bundle produced by the microwave process of the fifth embodiment using the oxidized fiber manufacturing method of the present invention 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 oxide fiber 21 is 51.2%, that is, the oxide layer 211 accounts for 51.2% of the oxide fiber 21; The oxidized fiber yarn bundle produced by the microwave process of the inventive oxidized fiber manufacturing method has a carbon fiber yarn bundle tensile strength of 1.17 times that of Comparative Example 1, 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 oxide layer 211 occupies 61.5% of the oxidized fiber 21; Example 3 uses the microwave manufacturing process of the method for manufacturing an oxidized fiber of the present invention The tensile strength of the carbon fiber yarn bundle after the final carbonization of the finished oxidized fiber yarn bundle is 1.23 times that of Comparative Example 1, 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 oxide layer 211 accounts for 82.7% of the oxidized fiber 21; Embodiment 2 The oxidized fiber yarn bundle made by the microwave process of the oxidized fiber manufacturing method of the present invention, and its final The tensile strength of the carbon fiber bundle after carbonization is 1.27 times that 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 oxide layer 211 accounts for 91.3% of the oxidized fiber 21; Example 1 The tensile strength of the carbon fiber yarn bundle after the final carbonization of the oxidized fiber yarn bundle made by the microwave process of the method for producing oxidized fiber of the present invention It 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 oxide fiber 21 is 99.0%, that is, the oxide layer 211 accounts for the oxide fiber 99.0% of 21.

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

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

In practice, the fiber yarn bundle 20 may be one of polyacrylonitrile (PAN), pitch, or other organic fibers. Of course, after the oxidized fiber undergoes a microwave action of 24 kW/m ² on the fiber yarn bundle 20 for 10 minutes, the oxidized layer 211 of the oxidized fiber 21 in the oxidized fiber yarn bundle 20A accounts for the oxidized fiber 219.0%, 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 traditional conventional technology, the method for manufacturing oxidized fiber 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 subjected to microwave focused oxidation treatment accounts for at least 50% of the cross-sectional area of the oxidized fiber, effectively reducing the oxidized fiber sheath-core structure, even The oxidized fiber can achieve no obvious sheath-core structure, and the performance of carbon fiber can be improved in a more positive and reliable way.

The above-mentioned embodiments are only to illustrate the technical ideas and features of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but cannot limit the patent scope of the present invention, That is to say, any equivalent changes or modifications made in accordance with the spirit disclosed by 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 tow 20A‧‧‧oxidized fiber yarn bundle 21‧‧‧oxidized fiber 211‧‧‧Oxide layer 212‧‧‧Core 30‧‧‧Transmission unit 31‧‧‧ Feeding unit 32‧‧‧Winding unit 33‧‧‧ furnace body 331‧‧‧Air inlet 332‧‧‧ vent 34‧‧‧Insulation unit 40‧‧‧Microwave processing unit 41‧‧‧ Magnetron 42‧‧‧Gas supply unit 50‧‧‧Control unit S01‧‧‧Provide yarn bundle steps S02‧‧‧Microwave processing steps

Figure 1 is a schematic diagram of a conventional core structure of oxidized fibers. Figure 2 is a basic flow chart of the method for manufacturing oxidized fibers of the present invention. Figure 3 is a schematic diagram of the structure of the transmission unit and the microwave processing unit of the method for manufacturing oxidized fibers of the present invention. Fig. 4 shows the manufacturing method of the oxidized fiber of the present invention with microwave focusing treatment of 12kW/m2, 16 kW/m2, 20 kW/m2, 24 kW/m2 on the fiber yarn bundle and the traditional heating process acting on the fiber yarn bundle Graph of oxidation degree of oxidized fiber. Fig. 5 is a graph showing the degree of cyclization of oxidized fibers after 24 minutes, 4 minutes, 5 minutes, 10 minutes, and 15 minutes of fiber knitting with a 24 kW/m2 microwave focusing treatment method of the present invention. Fig. 6 is a solid image view of an oxidized fiber cross-section in an oxidized fiber yarn bundle produced by the method for manufacturing an oxidized fiber of the present invention using a 24 kW/m2 microwave focusing treatment on the fiber yarn bundle for 5 minutes. Fig. 7 is a solid image view of an oxidized fiber cross-section in an oxidized fiber yarn bundle manufactured by a method for manufacturing an oxidized fiber of the present invention using a 24 kW/m2 microwave focusing treatment on a fiber yarn bundle for 10 minutes. Fig. 8 is a solid image of the oxidized fiber cross-section in the oxidized fiber yarn bundle manufactured by the method for manufacturing an oxidized fiber of the present invention using a microwave focusing treatment of 24 kW/m2 on the fiber yarn bundle for 15 minutes. Figure 9 is another flow chart of the method for manufacturing oxidized fibers of the present invention. Figure 10 is a schematic diagram of the furnace structure of the method for manufacturing oxidized fiber of the present invention. Figure 11 is a schematic diagram of the structure of the oxidized fiber of the present invention.

S01‧‧‧Provide yarn bundle steps

S02‧‧‧Microwave processing steps

Claims (6)

An oxidized fiber manufacturing method, suitable for preoxidizing a fiber yarn bundle (20) into an oxidized fiber yarn bundle (20A), the fiber yarn bundle (20) is composed of a fiber or a plurality of the fibers assembled into a bundle, The oxidized fiber yarn bundle (20A) is composed of an oxidized fiber (21) or a plurality of the oxidized fibers (21) assembled into a bundle. The oxidized fiber manufacturing method includes the following steps: a. providing a conveying unit (30) and A microwave processing unit (40); b. providing the fiber yarn bundle (20), and placing the fiber yarn bundle (20) in 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. Start the microwave processing unit (40), a microwave condition is generated by the microwave processing unit (40); the microwave condition includes: a microwave frequency, the microwave frequency system Between 300~300,000MHz; a microwave power, the microwave power is between 1~1000kW/m2; an operating temperature, the working temperature is between 100~600 ℃; a processing time, the processing time is between 1~ 40 minutes; and, a gas atmosphere, the gas atmosphere is one of oxygen, air, ozone or a mixture thereof; d. start the transfer unit (30), the fiber yarn bundle (20) is driven by the transfer unit (30) Under the microwave condition for a treatment time, the fiber yarn bundle (20) becomes the oxidized fiber yarn bundle (20A), and the fiber yarn bundle (20) is wound in a stack in a furnace body (33) Continuously receiving the irradiation of the microwave processing unit (40), wherein 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 of the furnace body (33) End, then transferred from the rear end of the furnace body (33) to the front end of the furnace body (33), and then from the front end of the furnace body (33) to the rear end of the furnace body (33), In this way, the rewinding is repeated until it is transferred from the rear end of the furnace body (33) into the oxidized fiber yarn bundle (20A) according to requirements; The conveying unit (30) is provided with a feeding unit (31) for providing the fiber yarn bundle (20), a winding unit (32) for continuously conveying the fiber yarn bundle (20), and the fiber yarn bundle (20) The furnace body (33) passing through; the microwave processing unit (40) is provided with a magnetron (41) for generating the microwave frequency and the microwave power at the furnace body (33), and is provided with There is a gas supply unit (42) for passing the gas atmosphere into the furnace body (33); the winding unit (32), the magnetron (41) and the gas supply unit (42) are connected with a control The unit (50) is electrically connected. The method for manufacturing an oxidized fiber according to claim 1, wherein the microwave power is between 10 and 24 kW/m ² . The method for manufacturing oxidized fiber according to claim 1, wherein the microwave frequency is between 2000 and 3000 MHz, and the operating temperature is between 150 and 350°C. The method for manufacturing an oxidized fiber according to claim 1, wherein the fiber yarn bundle (20) is one of polyacrylonitrile (PAN) fiber, pitch fiber or other organic fiber. The method for manufacturing oxidized fiber according to claim 1, wherein a heat preservation unit (34) is provided inside the furnace body (33). The method for manufacturing oxidized fibers according to claim 5, wherein the heat preservation unit (34) is one or a combination of metal oxides, carbides, and microwave high-sensitivity materials.

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