KR102447735B1 - INFUSIBLE TREATMENT DEVICE ON PCS SHORT FIBER AND METHOD FOR MANUFACTURING SiC SHORT FIBER USING THE SAME - Google Patents

Abstract

The PCS short fiber infusibility device includes: a chamber 10 provided with a gas inlet and an outlet, an openable door 12 mounted thereon, and horizontally disposed; a PCS fiber mounting table 20 spaced apart from the bottom surface of the chamber by a predetermined height and having a plurality of through-holes formed therein; an infusible gas generating body accommodating space 40 formed between the bottom surface of the PCS fiber mounting table 20 of the chamber 10 and the bottom surface of the chamber 10; a vacuum device connected to the gas outlet of the chamber 10; and a control unit for controlling the type and amount of gas injected into the chamber 10 , pressure, temperature, and gas discharge time.

Description

PCS short fiber infusibility device and manufacturing method of SiC short fiber using the same

The present invention relates to a device for infusibility of short PCS fibers and a method for manufacturing short SiC fibers using the same. More specifically, it relates to a device for cutting PCS fibers and infusible treatment in a single fiber state, and to a method for manufacturing short SiC fibers using the infusible device of the PCS short fibers.

Silicon carbide (SiC) fibers are manufactured at high temperatures under an inert atmosphere, and because of their excellent mechanical properties at ultra-high temperatures, recent space aircraft engines, nuclear power plant internal structures, thermal power plant turbine blades, brake pads/disks, and guided weapons are built in. It is widely used in various fields such as parts and semiconductor jigs.

The raw material for manufacturing SiC fibers is polycarbosilane (PCS), which is thermally decomposed by heat treatment in an inert atmosphere and then converted into SiC, a ceramic, to become SiC fibers. However, the melt-spun PCS fiber is melted again in the heat treatment process and loses its fiber shape. Alternatively, chemical treatment is carried out in a halogen gas atmosphere to induce a crosslinking reaction of the PCS fibers to convert them to thermosetting. In addition, when the infusible-treated PCS fiber is heat-treated at about 1000° C. or higher in an inert atmosphere, the PCS fiber is thermally decomposed while maintaining its shape to produce a SiC fiber.

Since the conventional infusibility process of PCS fibers is performed in the form of continuous fibers, when the final use form of SiC fibers is a non-woven sheet, the SiC fibers are cut into short fibers and then In order to have a desired shape, it is put into a non-woven fabric forming jig, etc. and further heat-treated to complete the production of a non-woven SiC short fiber sheet. In this way, the inconvenience of re-heating the SiC fibers that have already been infusible and heat-treated occurs, thereby reducing the productivity of the non-woven SiC short-fiber sheet and increasing the manufacturing cost.

And, in the case of the SiC continuous fiber, there is a problem that the doping of the halogen material for imparting a function is not efficiently performed because the continuous fiber is composed of a large space. Accordingly, in order to impart a desired function such as a semiconductor function to the SiC continuous fiber, for example, after infusibility with iodine, heat treatment at about 1000° C. or higher, and additionally exposure to halogen gas such as Cl to be doped. there is trouble

In Korean Patent No. 10-1848388, Korean Patent No. 10-1848389, etc., mention is made of the process of infusibility when manufacturing a nonwoven fabric using SiC fibers, but most of the SiC fibers are cut into short fibers and applied to a nonwoven fabric forming jig. Since the SiC short fiber sheet in the form of a nonwoven fabric is manufactured by putting it in and heat-treating it again, the number of steps is many and complicated, and the number of manual operations by the operator is large and mass production is not easy, so a fundamental solution is not provided.

The present invention is to solve the above problems, and an object of the present invention is to produce a SiC short fiber nonwoven fabric sheet without a process of cutting the SiC fiber into short fibers and re-heating, so that the An object of the present invention is to provide a PCS short fiber infusible device capable of reducing process time and cost by simplifying the manufacturing process, and a method for manufacturing SiC short fiber using the same.

However, these problems are exemplary, and the scope of the present invention is not limited thereto.

The PCS short fiber infusibility device according to an embodiment of the present invention is provided with a gas inlet and an outlet, and the internal space can be kept airtight in any one of an air atmosphere, a nitrogen atmosphere, a vacuum atmosphere, an argon atmosphere, and a halogen atmosphere. a chamber equipped with a door that can be opened and closed in an upward direction so as to be horizontally disposed; a PCS fiber mounting table spaced apart from the bottom surface of the chamber by a predetermined height so as to be able to load the PCS short fibers and having a plurality of through holes formed therein; an infusible gas generating body accommodating space formed between the bottom surface of the PCS fiber mounting table of the chamber and the bottom surface of the chamber; a vacuum device connected to the gas outlet of the chamber; and a control unit for controlling the type and amount of gas injected into the chamber, pressure, temperature, and gas discharge time.

In the PCS short fiber infusibility device according to an embodiment of the present invention, the chamber and the PCS fiber mounting table may be made of a graphite material or a metal material, and then the surface may be coated with PTFE fibers.

In addition, in the PCS short fiber infusibility device according to an embodiment of the present invention, the control unit operates a vacuum device to exhaust the air inside the chamber to reach about 1*10 ^-2 torr, and then again It can be controlled to repeat the process of injecting nitrogen to reach about 760 torr three times.

In addition, in the PCS short fiber infusibility device according to an embodiment of the present invention, the amount of solid iodine charged into the infusible gas generating body storage space inside the chamber is the amount of the PCS loaded on the PCS fiber mounting table. about 5 to 15% by weight of the fiber.

In addition, in the PCS short fiber infusibility device according to an embodiment of the present invention, the inside of the chamber may be maintained at about 200°C.

In addition, in the PCS short fiber infusibility device according to an embodiment of the present invention, the inner wall surface of the chamber may be provided with a clasp for installing the PCS fiber mounting table.

In the PCS short fiber infusibility method according to another embodiment of the present invention, the PCS short fiber is loaded into the PCS fiber mounting table installed inside the chamber of the aforementioned PCS short fiber infusible device, and the bottom surface of the chamber and the PCS Charging the solid iodine into the storage space between the fiber mounting table; Creating an infusible atmosphere by operating a vacuum device to exhaust the air inside the chamber to reach a vacuum level of about 1*10 ^-2 torr, then injecting nitrogen again to reach about 760 torr three times ; and gasifying solid iodine by maintaining the temperature inside the chamber at about 200° C. during the infusible atmosphere composition step to cross-react with PCS short fibers.

In addition, in the method for infusibility of short PCS fibers according to another embodiment of the present invention, the amount of solid iodine charged into the infusible gas generator storage space inside the chamber is about the amount of the PCS fibers charged to the PCS fiber mounting table. 5 to 15% by weight.

In the method for producing short SiC fibers according to another embodiment of the present invention, the short PCS fibers prepared by the above-described method of infusibility of the short PCS fibers are heat-treated at about 1000° C. or higher in an inert atmosphere to produce SiC short fibers. can

According to an embodiment of the present invention made as described above, the PCS short fibers are effectively infusible by the infusible device consisting of two stages, and the non-woven SiC fibers are heat-treated with the PCS short fibers loaded with the infusible fibers loaded. By manufacturing the short fiber sheet, the SiC short fiber nonwoven fabric sheet can be manufactured without the process of cutting the SiC fibers into short fibers and re-heating. In addition, in a narrow space such as a graphite jig, doping of a halogen material for incompatibility and function of PCS short fibers can be simultaneously performed. Thereby, the manufacturing process of the SiC short fiber sheet of a nonwoven fabric shape can be simplified, and process time and cost can be reduced. Of course, the scope of the present invention is not limited by these effects.

1 is a diagram schematically showing a PCS short fiber infusibility device according to an embodiment of the present invention.
2 is a cross-sectional view in a state in which the PCS short fiber and the infusible gas generator are charged in the PCS short fiber infusible device of FIG. 1 .
3 is a plan view of the PCS short fiber infusible device of FIG. 1 in a state in which the opening and closing door is omitted.
4 is a modified example in which the lower end of the device in the PCS short fiber infusible device of FIG. 1 is deformed.
5 is a cross-sectional view in a state in which the PCS short fiber and the infusible gas generator are charged in the PCS short fiber infusible device of FIG. 4 .
6 is a view of a state before the PCS short fibers charged in the PCS short fiber infusibility treatment device is infusible.
7 is a view of a state after the PCS short fibers charged in the PCS short fiber infusibility device is infusible.
8 is a view of a state in which the PCS short fibers charged in the PCS short fiber infusibility device are heat-treated in an electric furnace after infusibility treatment;
9 is a FT-IR (Fourier Transform Infrared Spectroscopy) diagram before and after infusibility of short PCS fibers.
10 is a TGA (thermogravimetric analysis) diagram before and after infusibility of PCS short fibers.

Objects, features and advantages of the present invention described above will become more apparent through the following examples in conjunction with the accompanying drawings.

The following specific structural or functional descriptions are only exemplified for the purpose of describing embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms and described in the present specification or application. It should not be construed as being limited to the embodiments.

Since the embodiment according to the concept of the present invention may have various changes and may have various forms, specific embodiments are illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to a specific disclosed form, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and/or second may be used to describe various elements, but the elements are not limited to the terms. The above terms are used only for the purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, a first component may be named as a second component, and similar The second component may also be referred to as the first component.

When a component is referred to as “connected” or “connected” to another component, it may be directly connected or connected to the other component, but other components may exist in between. will have to be understood On the other hand, when it is mentioned that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle. Other expressions for describing the relationship between elements, that is, expressions such as “between” and “immediately between” or “adjacent to” and “directly adjacent to”, etc., should be interpreted similarly.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. As used herein, terms such as “comprise” or “have” are intended to designate that the described feature, number, step, operation, component, part, or combination thereof is present, and includes one or more other features or numbers, It should be understood that the possibility of the presence or addition of steps, operations, components, parts or combinations thereof is not precluded in advance.

Unless defined otherwise, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in each figure indicate like elements.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

1 is a schematic diagram of a PCS short fiber infusibility device according to an embodiment of the present invention; 2 is a cross-sectional view in a state in which the PCS short fibers and the infusible gas generator are charged in the PCS short fiber infusible device of FIG. 1; 3 is a plan view of the PCS short fiber infusible device of FIG. 1 in a state in which the opening and closing door is omitted.

In the method of manufacturing a short SiC fiber using the PCS short fiber infusibility device 100 according to the present invention, the SiC short fiber nonwoven fabric sheet can be manufactured without the process of re-heating the SiC fiber by cutting the short fiber into short fibers. The PCS short fiber infusibility device 100 of the present invention is (i) a door and heat treatment zone with airtight chambers that can be made in an air atmosphere, nitrogen atmosphere, vacuum atmosphere, argon atmosphere, etc. to enable infusibility of PCS fibers. consists of; (ii) a gas inlet (IN-LET) into which various gases to be used for infusibility, for example, air, nitrogen, argon, halogen, etc., can be injected; (iii) The PCS short fiber infusibility device is manufactured in two stages, a solid halogen material is charged at the bottom, and PCS short fibers are charged on the PCS fiber mounting table at the top, and the PCS fiber mounting table has a number of through holes. It has a structure in which halogen gas from the bottom rises to the top and reacts with short PCS fibers; (iv) PCS short fibers loaded on the PCS fiber tray are exposed to halogen gas by closing the opening/closing door of the PCS short fiber infusibility device chamber; (v) an electric furnace capable of heating the infusible device in which the PCS short fibers are charged as it is in order to infuse the PCS short fibers may be used; (vi) A gas outlet (OUT-LET) capable of discharging gas inside the chamber may be connected to a vacuum device so as to create an incompatible atmosphere atmosphere. In addition, in the manufacturing method of the short SiC fiber using the PCS short fiber infusibility device 100, the PCS short fiber infusibility device is used as it is in the electric furnace without taking out the PCS short fiber infusibility treatment device from the PCS short fiber infusibility device. It can be put and heat-treated to manufacture a SiC short fiber nonwoven fabric sheet. Thereby, the convenience of the process is added by manufacturing the SiC short fiber nonwoven fabric sheet without the process of taking out the SiC short fiber and putting it anew.

PCS short fibers for infusibility treatment in the PCS short fiber infusibility device 100 of the present invention are obtained by unwinding the PCS fibers from a bobbin (not shown) on which the PCS fibers are wound by a conventional technique to form PCS short fibers of a predetermined length. By cutting, as shown in FIG. 6 , it can be prepared by loading on the PCS fiber mounting table 20 . For example, the PCS fibers 30 may be cut into short PCS fibers of about 50 mm in length. The bobbin on which the PCS fiber is wound according to the prior art, for example, is melted by heating the material polymer in a melt spinning unit (not shown), and the melted material is extruded through a nozzle in a state where pneumatic pressure is applied to cool and It can be prepared by forming a PCS fiber yarn by solidifying it and winding it on the outer peripheral surface of a cylindrical bobbin.

The PCS short fiber infusibility device 100 according to an embodiment of the present invention is a chamber 10 having an airtight door and a heat treatment zone, and is disposed spaced apart by a predetermined height from the bottom surface of the chamber, PCS fiber mounting table 20 on which a plurality of through-holes are formed; a accommodating space 40 for an infusible gas generator formed between the PCS fiber mounting table and the bottom surface of the chamber in the chamber, and a vacuum device connected to the gas outlet of the chamber; and a control unit for controlling the state of the gas inside the chamber.

After loading the short PCS fibers 30 on the PCS fiber mounting table 20 disposed inside the chamber 10, the inner space of the chamber is set to any one of an air atmosphere, a nitrogen atmosphere, a vacuum atmosphere, an argon atmosphere, and a halogen atmosphere. The openable and openable door 12 may be hingedly mounted to keep it airtight. The chamber 10 is provided with a gas inlet (IN-LET) (not shown) for injecting gas and a gas outlet (OUT-LET) (not shown) for discharging gas, and the gas outlet A vacuum device (not shown) capable of discharging the gas inside the chamber is attached to create an incompatible atmosphere. The vacuum device may be a vacuum pump.

1 to 3, the PCS fiber mounting table 20 is spaced apart from the bottom surface of the chamber by a predetermined height so that the PCS short fibers 30 can be loaded inside the chamber 10. can be placed. A plurality of through holes 21 having a diameter of about 5 mm are formed in the mounting table 20, so that infusible gas (for example, , a halogen gas generated from solid iodine) passes through the through holes 21 and reacts with the short PCS fibers.

The PCS short fiber infusibility device according to an embodiment of the present invention is used in a horizontally arranged state, the PCS short fiber 30 is disposed on the upper part in the chamber 10, and the infusible gas generator ( 50) is arranged in a two-stage structure. As described above, since the interior of the chamber 10 is configured in two stages with the PCS fiber mounting table 20 as a boundary, the infusible gas generated from the infusible gas generator 50 disposed below rises while the mounting table Since it passes through the through-holes 21 of 20, the short PCS fibers 30 disposed thereon are exposed to the infusible gas and react with the infusible gas to proceed with the infusibility process.

According to a modified example of one embodiment of the present invention, as shown in FIGS. 4 and 5 , in order to easily place the PCS fiber mounting table 20 at a predetermined height from the bottom surface of the chamber 10, the chamber ( 10) may be installed on the lower portion of the inner wall surface of the locking projection (14). The inner diameter of the inner wall of the chamber 10 from the bottom of the chamber 10 to the height at which the PCS fiber placement table 20 is installed is the inner diameter of the inner wall of the chamber 10 above the PCS fiber placement table 20 . By making it smaller, it is possible to form the locking jaw 14 . It is preferable that the inner diameter of the inner wall of the chamber above the locking protrusion 14 is larger than the outer diameter of the PCS fiber mounting table 20 . In addition, in a modified example of one embodiment of the present invention, a plurality of PCS fibers of a predetermined length are placed on the bottom surface of the PCS fiber placement table 20 in order to arrange the PCS fiber placement table 20 at a predetermined height from the bottom surface of the chamber 10 . A leg part (not shown) may be installed.

Infusible device (jig) in which PCS short fibers and solid infusible gas generators are charged in a two-stage arrangement in order to heat and infusible the PCS short fibers charged on the PCS fiber mounting table 20 in the chamber 10 A heating body (eg, an electric oven) (not shown) that can be heated by putting 100 as it is may be used. The temperature inside the chamber 10 is maintained at about 200° C. so that the short PCS fibers do not melt in the process of infusibility treatment of the short PCS fibers by heating the heating body, It can be heated to a uniform temperature. In addition, one or more heating elements (not shown) may be installed on the inner wall or lid of the chamber 10 in order to heat the PCS short fibers charged on the PCS fiber mounting table 20 in the chamber 10 to make them infusible. have.

In the PCS short fiber infusibility device 100 according to the present invention, the temperature inside the chamber 10 is adjusted to about 200° C. in order to treat the PCS short fiber 30 charged on the PCS fiber mounting table 20 for infusibility treatment. When the infusible gas is generated from the infusible gas generator 50 while maintaining the In order to charge the infusible gas generator into the chamber, a storage space 40 for the infusible gas generator is provided between the bottom surface of the chamber 10 and the PCS fiber mounting table 20 . In the present invention, as the infusibility generator 50, solid iodine may be used, and the gasified iodine performs the modification and doping action of the PCS fiber. When the solid iodine charged into the storage space 40 of the infusible gas generator inside the chamber 10 is gasified at about 200° C., the iodine donates electrons, and the decomposition and crosslinking reaction of the CH compound occurs. , PCS fibers are modified into PCS fibers with increased molecular weight and yield, and at the same time, iodine is doped in the PCS fibers and remains, thus completing the infusibility treatment of the PCS fibers. In this infusibility process, a thermoplastic polymer is converted into a thermosetting polymer through a chemical reaction, and low molecular weight polymer units are converted into larger units through cross-linking or radical bonding. In the accommodating space 40 of the infusible gas generator inside the chamber, about 5 to 15% by weight of solid iodine of the short PCS fibers loaded on the PCS fiber mounting table 20 may be charged. If the amount of iodine in the solid phase is less than 5% by weight of the short PCS fibers, the incompatibility rate of the short PCS fibers is slow or the infusibility is not completed. At more than % by weight, the incompatibility effect of PCS short fibers is not enhanced.

The type, injection amount, pressure, temperature, and gas discharge time of the gas injected into the chamber 10 may be controlled by a controller (not shown).

Since the PCS short fiber infusibility device (jig) according to an embodiment of the present invention is exposed to highly corrosive halogen gas, it is preferably made of a material having corrosion resistance to halogen gas. Accordingly, the PCS short fiber infusibility device (jig) of the present invention may be made of a graphite material or a metal material, and then the surface may be coated with PTFE (Polytetrafluoroethylene) fibers. For example, the PTFE fiber may use Teflon (trade name).

Next, a method for infusibility of short PCS fibers and a method for manufacturing short SiC fibers using the same according to another embodiment of the present invention will be described.

First, a method for infusibility of PCS short fibers of the present invention will be described.

In the PCS short fiber infusibility method according to the present invention, the PCS short fiber is loaded and loaded on the PCS fiber mounting table 20 disposed inside the chamber 10 of the infusible device (jig) 100. Infusibility treatment is performed. PCS short fiber for infusibility treatment in the PCS short fiber infusibility device 100 is obtained by unwinding the PCS fiber from a bobbin (not shown) on which the PCS fiber is wound by a conventional technique to obtain a short PCS fiber ( 30), as shown in FIG. 6, may be prepared by loading on the PCS fiber mounting table 20. Here, the method of winding the PCS fiber on the bobbin may use a conventional technique. For example, PCS (Polycarbosilane), the starting material of SiC fiber, is heated to around 200 ~ 250°C to melt, and then discharged into a fiber form through the hole of the nozzle. (not shown), the PCS fibers are unwound from the PCS fiber bobbin and cut into units of a predetermined length to prepare the short PCS fibers 30 in order to treat the short PCS fibers.

In the method for infusibility of short PCS fibers according to the present invention, the step of loading the short PCS fibers into the PCS fiber mounting table 20 installed inside the chamber 10 (S10), and the inside of the chamber 10 into an infusible atmosphere It includes the step of composing (S20) and gasifying solid iodine to cross-react with PCS short fibers (S30).

Specifically, in the step (S10) of charging the PCS short fiber into the chamber, the opening/closing door 12 of the chamber 10 of the PCS short fiber infusibility device 100 described above is opened, and the chamber 10 inside PCS short fibers 30 are loaded and charged on the PCS fiber mounting table spaced apart by a predetermined height from the floor in the of iodine (50) is charged (see FIG. 2). It is preferable that a plurality of through holes 21 are perforated in the mounting table 20 so that the infusible gas can freely flow between the short PCS fibers 30 , so that the gas can pass therethrough. Here, the PCS short fiber infusibility device 100 is used in a horizontally arranged state, the PCS short fiber 30 is disposed at the upper part in the chamber 10, and the infusible gas generator 50 is disposed at the lower part. It consists of a two-tier structure arranged. As described above, since the interior of the chamber 10 is configured in two stages with the PCS fiber mounting table 20 as a boundary, the infusible gas generated from the infusible gas generator 50 disposed below rises while the mounting table Since it passes through the through-holes 21 of 20, the short PCS fibers 30 disposed thereon are exposed to the infusible gas and react with the infusible gas to proceed with the infusibility process.

In order to heat infusible by heating the PCS short fibers charged on the PCS fiber mounting table 20 in the chamber 10, the PCS short fibers and a solid infusible gas generator (eg, iodine) are placed in two stages. The infusible jig charged with the furnace is placed in a heating body (eg, an electric oven) to heat the infusible jig. In the heating body, the internal temperature of the chamber 10 of the infusible jig may be maintained at about 200° C. so that the PCS short fibers do not melt during the infusibility treatment process of the PCS short fibers.

PCS short fibers are charged on the PCS fiber mounting table 20 in the chamber 10, solid iodine is charged into the infusible gas generating body storage space, and then the opening/closing door 12 of the chamber 10 is closed.

Next, in the step of creating an infusible atmosphere (S20), for example, by operating a vacuum pump, which is a vacuum device, the air inside the chamber 10 is discharged to reach a degree of vacuum of about 1 * 10 ^-2 torr. After that, the process of injecting inert nitrogen gas to reach about 760 torr is repeated three times to create an incompatible atmosphere.

And in the step (S30) of crosslinking the PCS fibers, the infusible jig loaded with the PCS short fibers is put in a heating body such as an electric furnace as it is and heated to adjust the temperature inside the chamber 10 of the infusible jig 100 to the PCS Maintain 200℃ where the fiber does not melt. In this case, in order to prevent the PCS short fibers from scattering due to the flow of gas inside the chamber 10 during heat treatment in the electric furnace, the opening/closing door 12 of the chamber 10 is heat-treated in the electric furnace in a closed state. In this embodiment, after maintaining a vacuum degree of 1*10 ^-2 torr to create a halogen gas atmosphere, solid iodine corresponding to 5 to 15% of the weight of the PCS fiber is added to the space between the bottom of the chamber and the PCS fiber mounting table. (40) is charged. When the temperature inside the chamber 10 is maintained at about 200°C, the solid iodine, which is an infusible gas generator charged inside the infusibility equipment, is gasified, and the infusible gas diffuses inside the infusibility jig and reacts with the PCS short fibers and crosslinks. The incompatibilization reaction proceeds as the reaction takes place, and when about 3 hours have elapsed, the incompatibilization reaction is completed.

If the infusibility reaction time of the PCS fibers in the chamber was less than 3 hours, a phenomenon occurred that the entire PCS short fibers loaded on the PCS fiber mounting table 20 were not completely infusible. The incompatibility effect was not further enhanced. After infusibility treatment for 3 hours in the chamber, when the infusibility jig is cooled and the internal temperature of the oven is cooled to room temperature (about 25 ℃), take out the PCS short fiber infusibility device (infusibility jig) from the oven, The infusible jig containing the infusible PCS fiber is charged as it is in an electric furnace in an inert atmosphere, and heat-treated at about 1300°C in an inert atmosphere (eg, nitrogen gas atmosphere) to induce thermal decomposition of the PCS fibers to induce SiC manufactures short fibers. 8 is a photograph showing that the short PCS fibers 30 are pyrolyzed and manufactured into the short SiC fibers 60 . The SiC short fibers 60 after the heat treatment has been completed have a black color.

As described above, according to the present invention, the PCS short fibers are effectively infusible by the two-stage infusible device, and the device (infusible jig) loaded with the infusible PCS short fibers is heat treated as it is to form SiC in the form of a non-woven fabric. By manufacturing the short fiber sheet, the SiC short fiber nonwoven fabric sheet can be manufactured without the process of cutting the SiC fibers into short fibers and re-heating. Thereby, the manufacturing process of the SiC short fiber sheet of a nonwoven fabric shape can be simplified, and process time and cost can be reduced.

6 shows the state before the infusibility treatment in which the PCS short fibers are loaded on the mounting table, and FIG. 7 shows that the PCS short fibers are infusible and the color of the PCS short fibers is changed. PCS short fibers that have been infusibilized are yellow.

By this infusibility treatment, the thermoplastic PCS short fibers are converted to thermosetting, so that even if the temperature is raised above the softening temperature and melting temperature in the subsequent pyrolysis process, the SiC short fibers that do not soften or melt and maintain the fiber shape are formed. possible, and at the same time, the thermal decomposition yield can be improved.

test example

9 is a Fourier-transform infrared (FT-IR) spectroscopic analysis of PCS short fibers and PCS short fibers before infusibility treatment by the infusible device and infusible method of the PCS short fibers according to the present invention. is the lead

Since the short PCS fibers formed by melt spinning are thermoplastic, there is a problem of losing the shape of the fibers and sticking to each other when subsequent heat treatment (pyrolysis) is performed to make them into SiC short fibers. Therefore, in order to maintain the fiber shape even when the temperature rises, the process of making the short PCS fibers thermosetting is an infusibility treatment, and by this infusibility treatment, the CH bonds of the short PCS fibers are broken, CH-Si-CH, A CH-O-Si-CH bond is formed, and low molecular weight molecules are crosslinked with each other.

9 is a diagram showing that the CH bond was reduced and cross-linking occurred due to the incompatibilization of these short PCS fibers. In FIG. 9 , the horizontal axis represents a wave number, and the vertical axis represents transmittance. In FIG. 9, the solid line indicates the FT-IR spectroscopic analysis value after infusibility of the PCS short fibers, and the dotted line indicates the FT-IR spectroscopic analysis value before the infusibility of the PCS short fibers. As the peaks pointing downward in the diagram of FIG. 9 represent CH bonds, the size of the peak after infusibility indicated by the solid line is smaller than the size of the peak before infusibility indicated by the dotted line, so that the CH bond is reduced, that is, the crosslinking reaction This occurred, indicating that the infusibility treatment was accomplished. As shown in FIG. 9, in the PCS short fibers infusible by the infusible device and the infusible method according to the present invention, the CH peaks were significantly reduced compared to before infusibility, indicating that the crosslinking reaction occurred effectively by the halogen gas. Confirmed.

10 is a TGA (Thermal Gravity Analysis) diagram before and after infusibility of PCS short fibers. In FIG. 10 , the horizontal axis represents temperature, and the vertical axis represents mass. In FIG. 10, the solid line represents the thermal decomposition yield (residual amount) after infusibility of the short PCS fibers, and the dotted line represents the thermal decomposition yield before infusibility of the short PCS fibers. As shown in FIG. 10 , it can be confirmed that the thermal decomposition yield of short PCS fibers after infusibility is increased by about 22% by weight compared to the thermal decomposition yield of short PCS fibers before infusibility due to efficient incompatibilization. Therefore, it was confirmed that the yield of SiC short fibers, which is a final product formed by thermal decomposition of PCS short fibers according to the present invention, can be effectively improved by infusibility treatment.

As described above, according to the present invention, the PCS staple fibers are effectively infusible by the infusible jig consisting of two stages, and the jig loaded with the infusible PCS short fibers is heat-treated as it is to form a non-woven SiC staple fiber. By manufacturing the sheet, the SiC short fiber non-woven fabric sheet can be manufactured without the process of cutting the SiC fiber into short fibers and re-heating, thereby simplifying the manufacturing process of the non-woven-shaped SiC short fiber sheet, thereby reducing the process time and cost. have.

Although the present invention has been described with reference to the embodiment shown in the drawings, which is only exemplary, those of ordinary skill in the art to which the present invention pertains will understand that various modifications and equivalent other embodiments are possible therefrom. will be. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

10: chamber
12: opening and closing door
20: PCS fiber mount
30: PCS short fiber
40: infusible gas generator storage space
50: infusible gas generator
60: SiC short fiber
100: PCS fiber infusibility device

Claims (10)

delete delete delete delete delete delete delete delete PCS fiber mounting table 20 installed to be spaced apart by a predetermined height inside the chamber 10 of the PCS short fiber infusibility device 100 having an openable and openable door 12 so that the internal space can be kept airtight charging the PCS short fibers into the chamber 10 and charging the solid iodine into the storage space 40 between the bottom surface of the chamber 10 and the PCS fiber mounting table 20;
After operating the vacuum device to discharge the air inside the chamber 10 to reach the vacuum degree of 1*10 ^-2 torr, inject nitrogen again and repeat the process of reaching 760 torr 3 times to create an incompatible atmosphere step;
maintaining the internal temperature of the chamber 10 at 200° C. during the infusible atmosphere composition step to gasify solid iodine to cross-react with PCS short fibers; and
Comprising the step of heat-treating the short PCS fibers infusible in the crosslinking reaction step of the PCS short fibers at 1000° C. or more in an inert atmosphere
A method for manufacturing SiC staple fibers.
10. The method of claim 9,
In the iodine loading step, the amount of solid iodine charged into the infusible gas generator storage space 40 between the bottom surface of the chamber and the PCS fiber mounting table is 5 of the PCS short fibers loaded on the PCS fiber mounting table. to 15% by weight
A method for manufacturing SiC staple fibers.

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