KR100653929B1 - Product method for matrix pitch using carbon complex material reinforced carbon fiber - Google Patents

Abstract

A production method for matrix pitch using carbon complex material reinforced carbon fiber is provided to manufacture globular anisotropic mesophase pitch wherein globes are uniformly dispersed. The production method matrix pitch using carbon complex material reinforced carbon fiber includes the steps of: manufacturing anisotropic mesophase pitches containing 50-75% of globular anisotropic mesophase by performing thermal treatment at 450-500deg.C within 1 hour by using coal tar based isotropic pitches as a principal ingredient; and pulverizing the manufactured anisotropic mesophase pitches to have mean grain size of less than 40 micrometer. The glubular anisotropic mesophase pitches are manufactured without using inactive gas or oxidative gas.

Description

Substrate pitch manufacturing method for carbon fiber reinforced carbon composite material (carbon / carbon composite material) {PRODUCT METHOD FOR MATRIX PITCH USING CARBON COMPLEX MATERIAL REINFORCED CARBON FIBER}

1A: A polarization micrograph of a representative long time heat treatment pitch

1b: Polarization micrograph of a typical short time heat treatment pitch

2: Viscosity change curve with temperature rise of 100% anisotropic mesophase pitch

3: Viscosity change curve with temperature rise of spherical mesophase pitch

The present invention relates to a method for manufacturing a substrate pitch for producing carbon fiber reinforced carbon composite material (hereinafter referred to as carbon / carbon composite material) using coal pitch as a raw material, and the carbon / carbon composite material has recently been used in aircraft, automobiles and other transportation equipment. As a material developed to cope with the rapid development of related industries, it is one of the high-tech new materials which is not only lightweight but exhibits high strength and elastic modulus, but also maintains strength and corrosion resistance at high temperatures. Existing substrate pitches for carbon / carbon composites are prepared by separating only certain components of petroleum-based heavy oils and adding an inert gas, followed by heat treatment to produce mesophase pitches containing 5 to 40% of anisotropic mesofaces, In the present invention, unlike the conventional heat treatment conditions, the anisotropic content is 50% by volume ratio by heat treatment as it is without using an inert gas or an oxidizing gas, which is generally used in the heat treatment process. By manufacturing the spherical mesophase-containing substrate pitch to the above, a method for producing a high-yield substrate pitch for producing carbon / carbon composites having a high quality that can maintain a viscosity of 100 cP (centipoise) or less in the temperature range of 350 ~ 450 ℃ It is about.

Substrate pitches for the production of carbon / carbon composites should exhibit low viscosity at high temperatures, high fluidity and high carbon yields at high temperatures. In other words, the physicochemical instability of the substrate pitch has a direct effect on the properties of the product when the carbon / carbon composite is manufactured using the substrate pitch, which makes it impossible to maintain the stable quality of the product. It should be possible to show high carbon yield in the heat treatment process.

In addition, the substrate pitch for producing the carbon / carbon composite material has important characteristics such as anisotropy content and high temperature crystallinity as well as the above physicochemical properties. These properties vary depending on the raw materials and the manufacturing conditions. In general, substrate carbon for the production of carbon / carbon composites should have a low viscosity at a certain temperature range, but if it exhibits a low viscosity at an excessively low temperature range or a characteristic at a high temperature range, internal pore formation or low density may occur. It is not suitable.

Currently known methods for manufacturing substrate pitches for carbon / carbon composites include anisotropic pitches of 5 to 15% by heat treatment of an isotropic pitch at temperatures of 450 ° C. or lower, followed by anisotropic tissue at 300 to 350 ° C. under an inert atmosphere. Sedimentation at the lower part to produce a part containing no anisotropic tissue at all, and the pitch that does not contain the separated anisotropy is produced by sedimentation separation by the same method by repeating the heat treatment (日 昭 63-145392), oil refinery After separating the by-product FCC (fluid-bed catalytic heavy oil decomposition) residue from the organic solvent using an organic solvent, each component is mixed at a predetermined ratio and heat-treated at 380 to 420 ° C. for 1 to 6 hours in an inert atmosphere. After the pitch of 5 to 40% is manufactured, specific gravity separation is performed at 300 to 350 ° C. to separate and use only the anisotropic pitch of the lower part. (特 開平 6-248274 The method of manufacturing a carbon / carbon composite material includes thermoplastic resin, thermosetting resin, and isotropic pitch (JP11130553A2) as a substrate material, and thermosetting resin and a mixture of graphite powder added to a general pitch powder. (韓國 特 1995-0011212), method of manufacturing by depositing pyrolytic carbon on carbon fiber preform (preform) (체 國 特 2000-0049126, JP2000086382A2), isotropic pitch or nitride pitch as substrate carbon (JP11302086A2) is known.

Heat treatment under an inert atmosphere as described above to produce a pitch containing anisotropy, and then separated by using a specific gravity separation method can be used to produce a substrate pitch for producing carbon / carbon composites, but many Not only does it take time, but there are problems such as an increase in manufacturing cost. As a method of manufacturing a carbon / carbon composite, as described above, a polymer resin that is easily available and relatively inexpensive is often used. It is difficult to increase the density of the carbon / carbon composites, and the method of depositing the inside using pyrolytic carbon not only requires a very long time to manufacture, but also is not economical due to high manufacturing cost.

In order to solve the above problems, the present invention induces a thermal polymerization reaction of coal tar pitch having a softening point of 110 ° C. without introducing an inert gas or an oxidizing gas, thereby developing an anisotropic structure and basically forming a graphite structure. It is an object of the present invention to provide a method for producing a substrate pitch for producing a carbon / carbon composite having a spherical mesophase, not a ash phase, in a volume ratio of 50% or more and having a viscosity of 100 cP or less in a 350 to 450 ° C region.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention provides a method for producing a substrate pitch for producing a carbon / carbon composite, wherein in one step, an isotropic mesophase pitch as a main raw material is induced by thermal polymerization in a temperature range of 480 to 500 ° C. Preparing an anisotropic pitch of 50% or more and having a viscosity of 100 cP or less in a region of 350 to 450 ° C .; And it relates to a substrate pitch manufacturing method for producing a carbon / carbon composite material comprising the step of grinding the anisotropic pitch to an average particle size of 45㎛ or less.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

As the main raw material for preparing the substrate pitch for producing the carbon / carbon composite of the present invention, any softening point having a softening point of 90 to 120 ° C. and a fixed carbon content of 45 to 55% by weight may be used. It is preferable to use a high coal-based pitch. Heat treatment temperature is possible in the range of 450 ~ 550 ℃, it should be heat treated short in high temperature, long in the low temperature region.

It is well known that the 100% anisotropic mesoface pitch has the same or better properties than spherical mesophase pitch in the carbonization yield and anisotropy development during high temperature carbonization, but the 100% anisotropic mesoface pitch has the lowest viscosity. Exhibits 287 cP at 400 ° C., not only does not exhibit a viscosity below 100 cP, which is an optimum viscosity for producing a carbon / carbon composite, but also has a very short viscosity retention time that can maintain a minimum viscosity. It is difficult to use it extensively as a pitch.

The 100% anisotropic mesophase pitch is known to be very useful as a precursor pitch for producing pitch-based carbon fibers, and has a chemical composition and characteristics very similar to that of a substrate for preparing carbon / carbon composites. However, when used as a substrate pitch for producing carbon / carbon composites, there is a problem in that it cannot be used due to high viscosity and short pot life, and when the anisotropic content is too low, the high density of the carbon / carbon composite is caused by low carbonization yield and volatile formation. Since there is a difficult problem, the anisotropic mesophase pitch as the substrate pitch is preferably in the range of 50 to 70% of the anisotropic content.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example  One

Comparative Examples 1 to 4

A coal-based raw material pitch having a softening point of 110 ° C. and a fixed carbon content of 52% by weight was charged to a reactor, and a reaction product was obtained by heat treatment at a temperature of 380 ° C. to 500 ° C. for 2 hours. During the reaction, the generated oil was induced to flow out of the reaction system smoothly, and the atmosphere inside the reactor was not particularly controlled, and no stirring was performed. The prepared heat-treated material was measured the production state of the anisotropic sphere using a polarizing microscope, and the softening point was measured using a softening point meter and the results are shown in Table 1.

Table 1

        Classification Experience  Reaction temperature (℃)  Response time (hr)   Anisotropic Tissue Form Anisotropy Generation (vol%) Softening Point (℃)  Comparative Example 1 380 2hr  conception 10 173  Comparative Example 2 400 2hr  conception 30 190 Comparative Example 3 450 2hr Odd 80 310 Comparative Example 4 500 2hr Odd 100 Insoluble

As shown in Table 1, when the reaction temperature was relatively low at 400 ° C., the anisotropy formation rate was lower than 30%, and the softening viscosity was low at 200 ° C. or lower. On the other hand, when the heat treatment was carried out at 450 ℃ and 500 ℃ not only showed a high value of the anisotropic content of more than 80%, but also a very high value of softening viscosity 310 ℃ and insoluble or did not show melting characteristics. In addition, in the case of anisotropic tissue, as shown in FIG. 1A, spherical mesophase is included in the low temperature heat treatment of 400 ° C. or lower, but in the case of high temperature heat treatment of 450 ° C. or higher, the mass is generally shown.

In addition, as shown in FIG. 2, the viscosity of the anisotropic mesophase pitch prepared by heat treatment at 450 ° C. for 2 hours showed a minimum viscosity of 288 cP at 400 ° C. FIG.

Inventive Example  1 to 4

A coal-based raw material pitch having a softening point of 110 ° C. and a fixed carbon content of 52% by weight was charged to a reactor, and a reaction product was obtained by heat treatment at a temperature of 450 ° C. to 500 ° C. for 0.8 hour. During the reaction, the generated oil was induced to flow out of the reaction system smoothly, and the atmosphere inside the reactor was not particularly controlled and stirring was not performed. The prepared heat-treated water was measured by using a polarizing microscope to measure the formation state of the anisotropic sphere, and the softening point was measured using a softening point measuring instrument and the results are shown in Table 2.

TABLE 2

        Classification Experience  Reaction temperature (℃)  Response time (hr)   Anisotropic Tissue Form Anisotropy Generation (vol%) Softening Point (℃)  Inventive Example 1 450 1hr  conception 51 256  Inventive Example 2 470 1hr  conception 57 279 Inventive Example 3 480 1hr conception 63 283 Inventive Example 4 500 0.8hr conception 69 301

As shown in Table 2, when the reaction conditions were reacted at 450 ° C to 500 ° C within 1 hour, the overall anisotropic structure was contained in the range of 51 to 69%, and the softening point was 256 ° C to 301 ° C. Indicated. On the other hand, in the case of anisotropic structure, as shown in FIG. 1B, when heat-processing for 1 hour in 450 degreeC-500 degreeC area | region, it contains spherical mesophase.

In addition, the viscosity of the anisotropic mesophase pitch prepared by heat treatment for 1 hour as shown in Figure 3 showed a minimum viscosity of 100cP at 400 ℃, it showed a stable viscosity in the range 350 ℃ ~ 450 ℃.

As described above, not only spherical anisotropic mesophase pitch in which spheres are uniformly dispersed throughout the present invention can be manufactured, but also carbon / carbon stably maintaining a melt viscosity of 100 cP in a temperature range of 350 ° C. to 450 ° C. It can be seen that the substrate pitch for producing the composite can be produced in high yield.

Claims (3)

In the method of manufacturing the substrate pitch for producing carbon / carbon composites, a coal-based isotropic pitch is used as a main raw material, and an anisotropy having a spherical anisotropic mesophase content of 50 to 75% by heat treatment within a range of 450 ° C. to 500 ° C. within 1 hour. Preparing mesophase pitch; Substrate pitch manufacturing method for producing a carbon / carbon composite material comprising the step of pulverizing the prepared anisotropic mesophase pitch to less than 40㎛ The method of claim 1, wherein a spherical anisotropic mesophase pitch is produced without using an inert gas or an oxidizing gas. The method for producing a substrate pitch for producing carbon / carbon composites according to claim 1, wherein the spherical anisotropic mesophase pitch exhibits a melt viscosity of 100 cP or less in the region of 350 to 450 ° C.

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