JP2007526195A - Process for making short carbon fiber preforms using coal tar pitch binders. - Google Patents

Abstract

A method and product of forming a short carbon fiber preform using a coal tar pitch binder.
[Selection figure] None

Description

Priority claim

  This application is a continuation-in-part of US patent application Ser. No. 10 / 476,017 filed on Oct. 23, 2003, and is subject to the provisions of US Patent Act 119 (e) as of May 30, 2003. Claims the benefit of US Provisional Patent Application No. 60 / 475,107, filed on a daily basis.

  The present invention relates to a friction material preform using a coal tar pitch binder, and more particularly, to a short (aligned to a certain length) carbon fiber preform using a coal tar pitch binder and its manufacturing method.

  Coal tar is a major byproduct produced when cracking or coking coal into coke. While coke products are used as a fuel and reagent source for the steel industry, coal tar materials are distilled into a series of commercially viable self-sale fractions. Most coal tar materials that are distilled are pitch residues. Pitch residues are used not only for the production of aluminum refining anodes but also for the production of electrodes for electric arc furnaces used in the steel industry. In evaluating the characteristics of pitch materials, the performance of coal tar pitch materials, which are binders suitable for use in the production process of anodes and electrodes, has been emphasized in the past. Various characteristics such as softening point, specific gravity, proportion of quinoline-insoluble substance known as QI (quinoline insoluble matter) and coke value characterize the coal tar pitch applied to the various processes and industries.

  The softening point is a basic measurement used to determine the mixing, forming or impregnation temperature during the formation of the carbon product as well as determining the end point of the distillation process when producing the coal tar pitch. is there. The total softening point shown herein is in accordance with the Mettler method or ASTM (American Society for Testing and Materials) standard D3104. Additional properties described herein include QI (quinoline insoluble) that is used to determine the amount of solid and high molecular weight material in the pitch. QI can be referred to as an α-resin and standard test techniques used to determine the weight percentage of QI include ASTM standard D4746 or ASTM standard D2318. The percentage of toluene-insoluble material TI described herein is also determined by ASTM standard D4072 or D4312.

  Mirchi and Noel, in a document called “Polycyclic Aromatic Hydrocarbons in the Pitch Used in the Aluminum Industry” distributed at “Carbon '94” in Granada, Spain. (Cyclic aromatic hydrocarbon) content was described and classified. The substances were classified according to their carcinogenic or mutagenic effects on living tissue. The paper identified 14 PAH substances that the US Environmental Protection Agency determined to be potentially harmful to public health. Based on a standard random assignment that assigns a factor of 1 to benzo (a) pyrene, B (a) P, a relative order of carcinogenic effects is assigned to each of the 14 substances. It is not necessary to individually refer to each of the 14 types of substances, and by converting the total total PAH content into B (a) P equivalents that are useful abbreviations for determining the toxicity of substances, the potential toxicity of pitch materials can be reduced. Can be estimated.

  A typical coal tar binder pitch has the characteristics shown in Table I.

Table I
Softening point, ° C 111.3
Toluene insoluble matter, weight% 28.1
Quinoline insoluble matter, weight% 11.9
Coke value, weight% by modified Conradson method (residual carbon content test method) 55.7
Ashes, wt% 0.21
Specific gravity, 25/25 ° C 1.33
Sulfur, weight% 0.6
B (a) P equivalent, ppm 35,000

  In general, two drawbacks have recently emerged when using coal tar pitch, particularly in the aluminum industry. The first drawback is the increased sensitivity of the aluminum refining anode material and usage to the environment. Another drawback is the reduced supply of raw coal tar from the coke production process. The caustic consumption has been significantly reduced due to various factors, which has reduced the availability of raw coal tar. In the near future, the production decline of the source material was expected to increase gradually, and during certain periods, alternative resources and alternative products were required. However, no commercially viable alternative to the coal industry pitch tar pitch has been developed.

  There are two types of conventional coal tar distillation methods, continuous and batch. The continuous distillation method includes a step of supplying a certain amount of a material to be distilled, that is, coal tar, and removing a certain amount of a product or residue, that is, coal tar pitch. Conventional continuous distillation processes, usually carried out at pressures between 60 mmHg and 120 mmHg and in the temperature range of 350 ° C. and 400 ° C., can produce coal tar pitches with a maximum softening point of usually about 140 ° C. The batch distillation method can be considered to be performed in a crucible, similar to boiling water. The longer the residence time of coal tar in the crucible, the higher the heating temperature level. A higher softening point at a temperature of 170 ° C. or lower can be achieved using a batch distillation method, but the combination of a high heating temperature and a long residence time decomposes coal tar pitch and eliminates an unnecessary intermediate phase (liquid crystal phase or mesophase ) A pitch may be generated. The processing time for distillation of coal tar using known continuous and batch distillation methods ranges from minutes to hours depending on the coal tar pitch product to be produced.

  Expose the material in a high temperature range of approximately 300 ° C. to 450 ° C. and in a low pressure range of approximately 5 Torr or less in a distillation vessel to remove higher molecular weight, less volatile components to lower molecular weight, more volatile components High efficiency evaporative distillation methods are known. The high-efficiency evaporative distillation process can be performed using a conventional distillation apparatus that operates in the specific temperature range and pressure range and has enhanced decompression performance. In addition, a highly efficient vaporization distillation method commonly called a WFE method can be performed by a thin film distillation apparatus, that is, an apparatus known as WFE. Similarly, a high-efficiency evaporative distillation method generally called a thin film evaporator method can be performed by an apparatus known as a thin film evaporator. As an efficient and relatively fast method of continuously distilling material, WFE and thin film evaporator methods may be used. In general, the WFE and thin film evaporator methods simultaneously reduce the pressure to a pressure range of approximately 5 Torr or less, while the temperature range is approximately 300 ° C. to 450 ° C., usually on the heating surface that is the inner wall of the processing vessel or chamber. Forming a thin material layer. In the WFE method, a rotating material is brought close to the inner wall of the processing container to form a thin material layer. In contrast, the thin film evaporator of the thin film evaporator method usually has a spinner structure in which a thin material layer is formed on the inner wall of the processing vessel by centrifugal force. The WFE method and the thin film evaporator method involving continuous input of raw materials and outflow of discharged materials are continuous processes. Both the thin-film distillation apparatus and the thin-film evaporator are conventionally known.

  One prior art of the WFE device is described in the following Patent Document 1 in the name of Baird. The apparatus described in Patent Document 1 includes a cylindrical processing chamber or a cylindrical processing container. The processing chamber is surrounded by a temperature control jacket (cover) that introduces a heat exchange fluid. The processing chamber includes a supply port provided at one end and a product discharge port provided at the opposite end.

  Moreover, the processing chamber of the apparatus described in Patent Document 1 includes a steam chamber having a steam discharge port. A cooler and a pressure reducing means are arranged in communication with the steam outlet, and the generated steam can be condensed under a pressure condition of less than atmospheric pressure. A tubular rotating body extending from one end to the other end of the processing chamber is driven by an electric motor. A plurality of radial blades extending axially outward from the rotating body shaft are curved asymmetrically and extend radially from one end of the processing chamber to the other between the supply port and the product discharge port. The rotor blades are slightly extended with respect to the inner wall of the processing chamber, but extend almost uniformly in relation to the thin film, and when the rotor rotates, the rotor blades are processed on the inner wall of the processing chamber. Form a thin film, coating film or turbulent film of material.

In operation, the material to be processed is fed to the raw material inlet by a pump or gravity. The material is moved downward, and the material is formed into a thin film on the inner wall of the processing chamber by a rotating rotor blade. A heat exchange fluid such as steam is introduced into a temperature control jacket, and the inner wall of the processing chamber is heated to a preselected stable temperature to evaporate while controlling the components of the relatively volatile processing material. . The relatively less volatile material is recovered from the product outlet, and the evaporated and more volatile material is recovered from the steam chamber through the steam outlet.
US Pat. No. 4,093,479

  One major application of coal tar pitch is as a binder for carbon / graphite products. Applications of carbon / graphite products range from aluminum production anodes to fine graphite products used in electrical discharge machining. The carbon / graphite product contains two main components: petroleum coke and coal tar pitch. Coal tar pitch is a binder that holds the structure together. The main process in the production of the final product is a graphitization process for the graphite product following the mixing process, the forming process, the carbonizing process and the carbonizing process of the carbon product. The main problem experienced by the pitch in the process is that volatile materials are generated during the carbonization process. When volatile substances are generated, 1) organic compounds are released, and 2) two serious problems occur in which the density of the final baked product is lowered. The emission of volatile substances presents an environmental problem that must be addressed either by capturing or destroying the organic compounds that are generated. Lowering the density of the carbon / graphite product results in product quality degradation due to reduced strength, increased reactivity, and increased electrical resistance. Thus, there are advantages to carbon / graphite products that produce less volatile material.

  Automotive brakes are produced by combining many inorganic and organic substituents with phenolic resins. The process for producing automobile brakes is similar in some respects to the process for producing the carbon / graphite product. One serious problem facing automobile brakes is a characteristic called fading. The fade phenomenon is a phenomenon in which the friction characteristics of the friction material are lowered during heating. Car drivers experience a fade phenomenon when they continue to brake on a downward slope. When the brakes begin to heat up, the driver must step on the brake pedal more strongly to achieve the same braking performance. The fade phenomenon is considered to be caused by the thermal instability of the phenol resin binder of the friction material. When the brake begins to heat up, the phenolic resin begins to decompose and a gas layer is formed between the two sliding members. This gas layer provides friction losses that result in the need to step on the brake pedal more strongly. Therefore, there is an advantage in the brake configuration that reduces the fade phenomenon.

  Aircraft brakes are produced by carbon impregnation of carbon fiber preforms. The method used for carbon impregnation is called chemical vapor infiltration. When the methane gas in the preform is coke and the chemical vapor infiltration method is performed, a carbon fiber preform filled with carbon is obtained. Chemical vapor infiltration requires a very long processing time of 600 hours to produce the final product. Therefore, the carbon infiltration method with shortened processing time is advantageous.

  Natural rubber is used to produce many products used every day. Tires are rubber products that play a major role in real life. Tires are manufactured from many different rubber compositions. Different compositions are used to form tire treads, sidewalls, belt coatings and rims. Among the different rubber compositions used to form the tire, one of the most important characteristics is the adhesion between the rubber compositions. Therefore, a rubber composition having great adhesion is advantageous.

  The mesophase pitch is a highly organized pitch used in applications where performance and strength capable of conducting electricity or heat are important. An important study of forming mesophase pitch from coal tar pitch was conducted, but this study was only partially successful due to the quinoline insoluble content of the pitch. It has been found that quinoline insoluble particles in coal tar pitch inhibit the setting or binding of mesophase spheres, resulting in poor quality mesophases. Known methods for producing an intermediate phase from coal tar pitch require a filtration step or a centrifugation step to remove quinoline insolubles. These processes produce a very good effect and can produce a high quality mesophase, but the production price of the mesophase product is very high. Therefore, it is advantageous to produce a high quality mesophase at a lower price.

  The present invention relates to a method for producing a high softening point coal tar pitch using a high-efficiency evaporative distillation method, and a method for using the pitch and its application. In the production method of the present invention, a supplied coal tar pitch having a softening point in a temperature range of 70 ° C. to 160 ° C. is supplied into a processing vessel heated to a temperature range of 300 ° C. to 450 ° C. and maintaining an internal pressure within a pressure range of 5 Torr or less. Is done. The output coal tar pitch is recovered from the processing vessel. The output coal tar pitch has a softening point in the temperature range 140 ° C. to 300 ° C. and an intermediate phase of less than 5%. If the produced coal tar pitch contains an intermediate phase exceeding 5% in content, the performance of the carbon-carbon composite material as a binder is deteriorated when producing a graphite electrode and an anode used for producing aluminum. The preferred range of output coal tar pitch includes a softening point in the temperature range of 150 ° C. to 250 ° C. and an intermediate phase of less than 1%. The produced coal tar pitch preferably has a B (a) P equivalent of 24,000 ppm or less. The supplied coal tar pitch preferably has a softening point in the temperature range of 110 ° C. to 140 ° C., and the processing vessel is preferably heated to a temperature range of 300 ° C. to 450 ° C. Also preferably a low viscosity between 2 and 5 centistokes at 99 ° C. (210 ° F.), preferably a low B (a) P equivalent of 5,000 ppm or less B (a) P, coal tar or You may mix | blend plasticizers, such as coal tar which mix | blended the petroleum-type oil component which comprises a 30-60% mixture, with output coal tar pitch.

  The present invention also relates to a method for producing a mesophase coal tar pitch having 10 to 100% mesophase. In the production method of the present invention, a supply coal tar pitch having a softening point in the range of 70 ° C. to 160 ° C. is supplied into a processing vessel heated to a temperature range of 300 ° C. to 450 ° C. and kept inside the pressure range of 5 Torr or less. . A distillate having a softening point in the temperature range of 25 ° C. to 60 ° C. and free of quinoline insolubles and ash is obtained from the processing vessel. The distillate is heat treated at a temperature range of 370 ° C. to 595 ° C. for 3 minutes to 80 hours.

  The present invention also relates to a process for producing coal tar pitch that does not contain quinoline insoluble or ash. In this manufacturing method, a supplied coal tar pitch having a softening point of a temperature range of 70 ° C. to 160 ° C. is supplied into a first processing vessel heated to a temperature range of 300 ° C. to 450 ° C. and maintained at an internal pressure range of 5 Torr or less. A step of obtaining from the first treatment vessel a distillate having a softening point in the temperature range of 25 ° C. to 60 ° C. and containing no quinoline insoluble or ash content, and from a temperature range of 350 ° C. for 5 minutes to 40 hours. A step of heat-treating the distillate at 595 ° C., a step of distilling the heat-treated distillate to obtain a pitch having a desired softening point, and a second processing vessel heated to a temperature range of 300 ° C. to 450 ° C. And a step of supplying a pitch having a desired softening point and a step of recovering the produced coal tar pitch from the second processing vessel. The first processing container and the second processing container may be the same or different processing containers.

  In each production method of the present invention, instead of the supplied coal tar pitch, a hydrocarbon mixture such as a mixture of coal tar pitch and petroleum pitch may alternatively be used as the feedstock. The hydrocarbon mixture preferably contains at least 50% coal tar pitch.

  You may implement each manufacturing method of this invention using the conventional distillation apparatus, a thin film distillation apparatus, or a thin film type evaporator. Conventional distillation is limited to a softening point pitch at a temperature of 180 ° C.

  In short, at least one preferred embodiment of the present invention provides an output coal tar pitch used as a “regulator” in the production of carbon / graphite products and having a high softening point above 170 ° C. Contemplate extensively. By using the high softening point pitch product of the present invention to generate a smaller number of volatile materials, the problems associated with the generation of volatile materials during production can be addressed. The lower the amount of volatile material generated, the less organic compounds that are trapped or destroyed by the volatile material, and the resulting product is more dense and has superior properties in the final carbon / graphite product. It means that it can be granted. Also, the high softening point coal tar pitch portion of the resulting carbon / graphite product can be shrunk to improve the density and strength of the product. The heat conduction efficiency and electrical conduction efficiency of the resulting product are increased.

  Furthermore, at least one preferred embodiment of the present invention extensively contemplates a high softening point coal tar pitch for use as a binder in forming automotive brakes. Adding the high softening point pitch product of the present invention to the brake composition reduces the fade phenomenon because the pitch is very stable to high temperatures without decomposing and generating bubbles that induce the fade phenomenon can do.

  Furthermore, at least one preferred embodiment of the present invention extensively contemplates a high softening point coal tar pitch for use as a saturant in forming aircraft brakes. With the high softening point pitch of the present invention, the carbon fiber preform can be saturated by 95% saturation in about 1 hour. This preliminary short time saturation may reduce the time required for complete carbon saturation of the preform. The final aircraft brake manufactured using a high softening point pitch was tested with a dynamometer and showed excellent friction characteristic results.

  Furthermore, at least one preferred embodiment of the present invention contemplates a wide range of high softening point coal tar pitches used in the manufacture of rubber products. The rubber composition containing the pitch of the present invention showed excellent adhesive properties.

  Furthermore, at least one preferred embodiment of the present invention contemplates a wide range of distillates used to produce mesophase pitch. The distillate product of the present invention is a coal tar-inducing substance that does not contain quinoline insolubles, indicating the formation of a high quality mesophase. Moreover, in the economical aspect of the intermediate phase production of the present invention, a product can be obtained at a very low cost.

  Furthermore, at least one presently preferred embodiment of the present invention does not use a phenolic resin and uses a high softening point coal tar pitch as a means of blending short carbon fibers uniformly within the friction material preform. Contemplate. Aircraft and automobile brake preforms are typically formed using phenolic resin. In the present invention, the phenol resin used for manufacturing the preform is replaced with a high softening point pitch.

  In the present invention, using a high efficiency evaporative distillation method carried out in a processing vessel operating in a temperature range of 300 ° C. to 450 ° C. and a pressure of 5 Torr or less, a temperature range of 70 ° C. to 160 ° C., preferably 110 ° C. to 140 ° C. By processing the supplied coal tar pitch having a softening point at 0 ° C., a coal tar pitch having a high softening point and low volatility can be produced. Even if it is operated at a temperature less than the minimum temperature, the desired softening point cannot be imparted to the product material, and even if it is operated at a temperature exceeding the maximum temperature, thermal cracks and thermal deterioration occur in the product material. The temperature range is important. Similarly, if the pressure is higher than a certain maximum range pressure, a higher operating temperature that results in thermal cracking and thermal degradation of the product is required to achieve the desired softening point, so the pressure range is ,is important.

  In this invention, a production | generation process can be implemented using a WFE apparatus, and although the production | generation process using a WFE apparatus is demonstrated for convenience of explanation, this invention is not limited to this production | generation process. However, it will be understood that conventional distillation equipment and thin film evaporators can be used as long as they can operate at the temperatures and pressures described herein. When using a thin film evaporator, a film should preferably be formed on the inner wall of the thin film evaporator with a minimum thickness not less than the thickness of the maximum QI particles contained in the feed.

Any known WFE device can be used as long as the WFE device can be operated in a temperature range of 300 ° C. to 450 ° C. and a pressure of 5 Torr or less. Preferably, the WFE device should be able to operate at a coating speed range of 200 rpm to 3000 rpm with a minimum film thickness of 1 mm. The processing chamber or processing vessel wall of the WFE apparatus is heated between a temperature range of 300 ° C. and 450 ° C., preferably between 300 ° C. and 400 ° C. The appropriate supply rate of the supplied coal tar pitch to be introduced into the WFE apparatus depends on the processing surface area of the processing vessel. The feed rate is 50-500 kg / m ² (10-100 pounds per square foot) (surface area) / hour, preferably 175-250 kg / m ² (35-50 pounds per square foot) (surface area) / hour. . If the supplied coal tar pitch is fed to the WFE unit at a rate of 50 to 500 kg / m ² (10 to 100 pounds per square foot) (surface area) / hour, the residence time of the supplied coal tar pitch in the WFE unit is about 1 to 60 seconds. If the feed coal tar pitch is fed at a suitable rate of 35-50 pounds per square foot (surface area) / hour, the residence time of the feed coal tar pitch in the WFE apparatus is about 5-30 seconds. WFE equipment residue has a softening point in the range 140 ° C to 300 ° C, preferably in the range 150 ° C to 250 ° C and a minimum production in the range 0% to 5%, preferably in the range 0% to 1% This is an output coal tar pitch with an intermediate phase. When using conventional distillation equipment operating at specific temperatures and pressures, the output coal tar pitch has a softening point in the range of 140 ° C to 180 ° C. Using conventional distillation equipment, the residence time required to produce a produced coal tar pitch with a softening point in excess of 180 ° C. results in defects such as the formation of excess intermediate phases. To achieve a production coal tar pitch with a softening point in excess of ° C., it is necessary to use a WFE apparatus or a thin film evaporator. Also, by using a high efficiency evaporative distillation method such as the WFE method to promote the removal of high boiling PAH, especially benzo (a) pyrene, from the feed coal tar pitch, 24,000 ppm or less of B (a ) Producing coal tar pitch with P equivalents can be produced. The yield of output coal tar pitch at a given container temperature depends on the softening point of the supplied coal tar pitch.

Example 1
The supplied coal tar pitch with a softening point of 109 ° C. is 385 kg / m ² (with a softening point of 109 ° C. in a WFE unit having a vessel of 0.13 m ² (1.4 sq ft) operating at a temperature of 335 ° C. and an absolute pressure of 18.5 mmHg Feed at a feed rate of 77 pounds per square foot (surface area) / hour. The output coal tar pitch of the WFE equipment has a pitch yield of 85%. The laboratory analysis results of the produced coal tar pitch are shown in Table II below.

Table II
Softening point, ° C 140.6
Toluene insoluble matter, weight% 32.9
Quinoline insoluble matter, weight% 15.1
Coke value, modified Conradson method, weight% 64.9
Ash content, weight% 0.20
Specific gravity, 25/25 ° C 1.35
Beta resin, weight% 17.8

Example 2
In a WFE unit having a container of 0.13 m ² (1.4 sq. Ft) operating at a temperature of 335 ° C. and an absolute pressure of 10.4 mm Hg, the supplied coal tar pitch with a softening point of 109 ° C. is 475 kg / m ² ( 95 pounds per square foot) (surface area) / hour feed rate. The output coal tar pitch of the WFE equipment has a pitch yield of 73%. The laboratory analysis results of the produced coal tar pitch are shown in Table III below.

Table III
Softening point, ° C 163.0
Toluene insoluble matter, weight% 37.7
Quinoline insoluble matter, weight% 17.0
Coke value, modified Conradson method, weight% 71.6
Ash content, weight% 0.22
Specific gravity, 25/25 ° C 1.36
Beta resin, weight% 20.7

Example 3
A WFE unit having a 0.13 m ² (1.4 sq. Ft.) Vessel operating at a temperature of 350 ° C. and an absolute pressure of 5.0 mm Hg is fed with a feed coal tar pitch having a softening point of 109 ° C. of 65 lb / sq. Surface area) / hour. The output coal tar pitch of the WFE equipment has a pitch yield of 74.2%. The laboratory analysis results of the produced coal tar pitch are shown in Table IV below.

Table IV
Softening point, ° C 20.0
Toluene insoluble matter, wt% 42.2
Quinoline insoluble, wt% 18.2
Coke value, modified Conradson method, weight% 76.5
Ash content, weight% 0.27
Specific gravity, 25/25 ° C 1.378
Beta resin, wt% 24.1

Example 4
In a WFE apparatus having a container of 0.13 m ² (1.4 sq ft) operating at a temperature of 365 ° C. and an absolute pressure of 5.0 mmHg, the supplied coal tar pitch with a softening point of 109 ° C. is 67 lb / sq. Supplied at a feed rate of feet (surface area) / hour. The output coal tar pitch of the WFE equipment has a pitch yield of 67%. The laboratory analysis results of the produced coal tar pitch are shown in Table V below.

Table V
Softening point, ° C 225
Toluene-insoluble matter, weight% 48.9
Quinoline insoluble, wt% 23.3
Coke value, modified Conradson method, weight% 81.2
Ash content, weight% 0.24
Specific gravity, 25/25 ° C 1.365
Beta resin, weight% 25.7

  In the production of graphite electrodes and anodes used for the production of aluminum, the binder for carbon-carbon composite and friction material is in the range of 140 ° C to 300 ° C, preferably in the range of 150 ° C to 250 ° C. An output coal tar pitch having a softening point of can be used. Furthermore, the production of an aluminum anode containing Soderberg binder pitch by mixing a plasticizer with the produced coal tar pitch having a softening point in the range of 140 ° C. to 300 ° C., preferably in the range of 150 ° C. to 250 ° C .; A pitch with a softening point of 110 ° C. suitable for all other industrial applications where a low PAH content is required can be produced. The plasticizer preferably has a low viscosity between 2 and 5 centistokes at 99 ° C. (210 ° F.) and preferably has a low B (a) P equivalent of 5,000 ppm or less B (a) P. Coal tar blended with petroleum constituting 30 to 60% of the coal tar or the mixture may be used. One suitable plasticizer is the coal tar pitch mixture described in Mackenley et al., US Pat. No. 5,746,906, the disclosure of which is incorporated herein.

  Instead of feed coal tar pitch, in another embodiment of the invention, alternatively, a hydrocarbon mixture such as a mixture of coal tar pitch and petroleum pitch may be used as feed. In the present embodiment, the hydrocarbon mixture preferably has a coal tar pitch content of at least 50%. The distillate produced when using a hydrocarbon mixture as the feed can be used in the process described below.

  The distillate produced by processing the feed coal tar pitch in the WFE unit has a QI in the 0% to 0.5% range and an ash content in the 0% to 0.1% range as described herein. This means that it contains neither quinoline insolubles nor ash. A distillate free of insoluble quinoline and ash is preferred for at least two reasons. First, it is known that distillate can be used to produce materials that are used as impregnation pitch to fill the pores in the carbon structure, with QI and ash hindering the ability to fill the pores. is there. Second, it is known that distillate can be used to produce mesophase pitch, and QI inhibits mesosphere sphere binding. The distillate includes a pitch having a softening point in the range of 25 ° C to 60 ° C.

  The desired high softening using the distillate, free of quinoline insolubles and ash, by subjecting the distillate to a first heat treatment at a temperature between 350 ° C. and 595 ° C. for 5 minutes to 40 hours A pitch of points can be generated. For example, the heat treatment step can be carried out by storing the distillate in a flask equipped with a short distillation column and heating and stirring the distillate under a slight vacuum of an absolute pressure of 600 mmHg or less. A pitch having a softening point in the range of 60 ° C. to 110 ° C. is obtained by the heat treatment step of the distillate. Thereafter, the distillate heat-treated by a known conventional means is distilled to obtain a pitch residue having a desired softening point. The resulting pitch can be used to produce carbon fibers and fuel cells. Alternatively, quinoline insolubles produced by heat treatment and distillation using a high-efficiency evaporation distillation method such as a WFE method or a thin film evaporator method at a temperature in the range of 300 ° C. to 450 ° C. and a pressure of 5 Torr or less, and The ash-free pitch may be further processed to produce a pitch with a narrow boiling range and no quinoline insoluble content, the narrow boiling range pitch being the residue of further processing.

Example 5
Distilling a distillate having a softening point of 25-30 ° C. produced from a supplied coal tar pitch having a softening point of 110 ° C. for about 8 hours at 360 ° C. to produce a pitch having a softening point of 60 ° C. it can. A 60 ° C. softening point pitch at a top (overhead) temperature of 400 ° C. can be distilled in a batch / pot distiller to produce a pitch with a softening point of 98.9 ° C. in 70% yield. The results of laboratory analysis of the resulting pitch are shown in Table VI below.

Table VI
Toluene insoluble matter, weight% 18.3
Quinoline insoluble matter, weight% 0.5
Coke value, modified Conradson method, weight% 46
Ash content, wt% 0.04
Specific gravity, 25/25 ° C 1.29
Beta resin, weight% 17.8

  Alternatively, by subjecting the distillate to a temperature range of 370 ° C. to 595 ° C. for a period of 3 minutes to 40 hours, an intermediate phase content in the range of 70% to 100%, preferably in the range of 75% to 85% A mesophase pitch having a quantity may be produced from the distillate. The yield of mesophase pitch is in the range of approximately 70% to 100%. Mesophase pitch can be used for carbon fibers, lithium ion batteries and graphite foam (foam).

  Instead of feed coal tar pitch, in another embodiment of the invention, alternatively, a hydrocarbon mixture such as a mixture of coal tar pitch and petroleum pitch may be used as raw material. The hydrocarbon mixture of the present embodiment preferably has a coal tar pitch content of at least 50%.

Carbon / graphite product The present invention also relates to the use of produced coal tar pitches with high softening points. In the first application, in a method for producing a carbon / graphite product that produces a coal tar pitch with a softening point of 110 ° C. from coke in a conventional manner, preferably in the range of 150-250 ° C., more preferably 160- An output coal tar pitch having a high softening point in the range of 220 ° C., most preferably in the range of 170-200 ° C., can be used as the “regulator”. One embodiment of the present invention includes replacing a coal tar pitch with a softening point of 110 ° C. with a coal tar pitch with a softening point of 160 ° C. during the production of the carbon / graphite product. In another embodiment, in the production of the carbon / graphite product, an output coal tar pitch having a high softening point is used instead of a portion of the coke.

Example 6
160 ° C. instead of the 110 ° C. softening point pitch used to form 0.77 cm (5/16 inch) diameter × 12 inch inch perforated troughs (goose rods) by extrusion. Use the softening point pitch. This pitch is mixed with coke at an input rate of about 60% by weight and extruded into a final piece. The formation is fired and graphitized. Properties of the product are shown in Table VII.

Table VII

  Since a pitch with a high softening point of 160 ° C., which is higher than a normal pitch of 110 ° C., was used, the produced carbon-graphite product has improved density characteristics, strength characteristics and resistivity characteristics. The graphite density was improved by 3.8% and the graphite strength was improved by 14.3%.

  A softening point pitch of 180 ° C. is used in place of the coke powder used for graphite pieces of 1-5 / 8 inch diameter × 24 inches long and 1-5 / 8 inch diameter × 48 inches long. During compounding, 10% by weight of coke powder is removed and 15% by weight of 180 ° C. pitch is added to the mixture as a powdered solid. The mixture is calcined and graphitized. Properties of the product are shown in Table VIII.

Table VIII

  The carbon-graphite product produced using a 180 ° C. high softening point pitch has improved density and electrical resistivity characteristics over normal coke. The density of graphite was improved by 4.7% and the electrical resistivity was improved by 6.7%.

Friction material In a second application, the produced coal tar pitch is used in the production of friction materials for brakes used in various transportation means such as aircraft and automobiles.

  When producing a semi-metallic automobile brake, the call preferably has a high softening point in the range of 150-250 ° C, more preferably in the range of 170-240 ° C, most preferably in the range of 180-230 ° C. Tar pitch is used as a binder. It is preferred to use a crosslinking additive to further increase the softening point of the pitch after curing to a temperature in the range of 177 ° C. (350 ° F.) to 232 ° C. (450 ° F.).

Example 7
A softening point coal tar pitch of 180 ° C. can be used in place of 3% by weight of the total 8% by weight phenolic resin in a semi-metallic automobile brake pad.

Table IX
A normal (control) semi-metallic automotive brake pad composition is as follows.

34 wt% Steel fiber 25 wt% Sponge iron 15 wt% Graphite 5 wt% Petroleum coke 8 wt% Phenol resin 6 wt% Filler 3 wt% Friction polymer 3 wt% Magnesium oxide 1 wt% Aluminum oxide

Mixing 3% by weight of 8% by weight phenolic resin was removed and 180 ° C. softening point coal tar pitch powdered to 50% through a 200 mesh sieve was added instead of 3% by weight, and then mixed at room temperature.

Table X
The semi-metallic automotive brake pad composition according to Example 7 has the following composition:

34 wt% Steel fiber 25 wt% Sponge iron 15 wt% Graphite 5 wt% Petroleum coke 5 wt% Phenol resin 6 wt% Filler 3 wt% Friction polymer 3 wt% Magnesium oxide 1 wt% Aluminum oxide 3 wt% 180 ° C softening Point coal tar pitch

A semi-metallic brake mixture is molded at a pressure of 0.54 tons / cm ^{2 to} 0.62 tons / cm ² (3.5 to 4.0 tons / square inch) at a temperature of 138 ° C. (280 ° F.). The When 45 seconds, 90 seconds, 135 seconds and 180 seconds have elapsed, the pressure is released and the molded body is taken out. The total time of the molding cycle is 5 minutes. The brake pad is then post-cured at 177 ° C. (350 ° F.) for 4 hours. The properties of the composition are shown in Table XI.

  As shown in Table XI, coal tar pitch is used to show the results of improved wear, particularly high temperature wear (425 ° C.). As shown in Tables XI (1), (2), compared to the control composition (no pitch), Example 7 shows 29 weight loss (mm) and weight loss (grams) of 29. % And 24% decrease. As shown in Table XI (3), the use of the coal tar pitch of the present invention improves the fade heat cycle minimum by 7.5%. When using coal tar pitch as compared to the control composition, a more stable coefficient of friction is obtained when the brake pads are tested over the full range of energy states. The table shows this based on the effect of the numerical values specified.

  When producing aircraft brakes, a coal tar pitch having a high softening point, preferably in the range of 160-240 ° C, more preferably in the range of 170-220 ° C, most preferably in the range of 180-200 ° C, Used to saturate carbon fiber preforms for aircraft brakes.

Example 8
Using a low QI (quinoline insoluble) 180 ° C. softening point coal tar pitch, aircraft brake carbon fiber preforms can be saturated and the porosity of the preform can be reduced from 75% to 5% by volume in the following manner. .

A carbon fiber preform having about 25% by volume carbon fiber is placed under vacuum pressure (less than 10 mmHg) and heated to 325 ° C. A low QI (less than 10% by weight) 180 ° C. softening point coal tar pitch is introduced into the carbon fiber preform at 325 ° C. A carbon fiber preform saturated with coal tar pitch is pressurized with nitrogen to 1.05 kg / cm ² (15 psig). The saturated carbon fiber preform is cooled. The saturated carbon fiber preform is further processed, starting with a densification process using chemical vapor infiltration (CVI).

  Prior to the CVI process, by saturating the carbon fiber preform with coal tar pitch to increase the initial density of the carbon fiber preform, as shown in Table XII, the CIV process required to meet the density specification Real time can be significantly shortened (about 30%). This has an excellent cost advantage in the processing of carbon fiber preforms that make aircraft brake discs.

Table XII (supra)
Rubber product In another application of the present invention, coal tar having a high softening point, preferably in the range of 100-200 ° C, more preferably in the range of 120-180 ° C, most preferably in the range of 140-180 ° C. Using the pitch, a rubber product such as a tire composition containing natural rubber in the composition is produced.

Example 9
6 parts of 140 ° C. softening point coal tar pitch is blended into the formulation of a wire belt coat composition containing 0.5 parts of additional sulfur.

Table XIII
A typical wire belt coat composition formulation (control composition) has the following composition:

100 parts natural rubber 55 parts carbon black 15 parts silicon dioxide 4 parts paraffinic petroleum 2 parts stearic acid 6 parts zinc oxide 1 part antioxidant, TMQ (trimethylquinoline)
0.75 parts Cobalt naphthenate 3 parts Resorcinol 2.5 parts HMMM (Hexamethoxymethylmelamine)
4.0 parts Sulfur 0.9 parts TBSI (tertiarybutylbenzothiazolesulfenimide)

  Resorcinol and HMMM are removed from the formulation of the wire belt coat composition and 6 parts of a 140 ° C. softening point coal tar pitch, powdered to 50% through a 200 mesh sieve, and an additional 0.5 parts of sulfur are added.

Table XIV
The formulation of the wire belt coat composition according to Example 9 (coal tar pitch formulation) has the following composition:

100 parts natural rubber 55 parts carbon black 15 parts silicon dioxide 4 parts paraffinic petroleum 2 parts stearic acid 6 parts zinc oxide 1 part antioxidant, TMQ
0.75 parts Cobalt naphthenate 4.5 parts Sulfur 0.9 parts TBSI
6 parts 140 ° C softening point coal tar pitch

  A wire belt coat composition was prepared as follows.

Stage 1
Starting temperature, ° C: 66-71 (° F: 150-160) Rotor speed, rpm: 70 ram pressure, kg / cm ² : 3.49 (50 psi)
time,
Min ingredients or steps 0 1/2 rubber, silicon dioxide, 1/2 of carbon black, 1/2 Rubber 1-3 / 4 TBSI, zinc oxide, HMMM, all 3-1 / 2 Sweep 5 Sweep 6 dump except sulfur

  Set mill roll temperature to 54 ° C (130 ° F). Band Stage I mix.

  Cut each side 3 times, pass 3 edges, cool sheet.

Stage II
Starting temperature, ° C: 38-43 (100-110 ° F) Rotor speed, rpm: 60 ram pressure, kg / cm ² : 3.49 (50 psi)
Hour, Minute Component or Procedure 0 1/2 Stage I, TBSI, Sulfur, HMMM, Zinc Oxide, 1/2 Stage I
1 sweep 2-1 / 2 dump

  Set mill roll temperature to 54 ° C (130 ° F). Band Stage II mixing.

  5 cuts on each side, 5 end passes, 2 minutes particle set, sheet cooling.

  Allow the formulation to stand for 24 hours at 22 ° C. (72 ° F.) before testing and curing.

  Properties of the wire belt coat composition using the coal tar pitch composition are shown in Table V.

  The test results show improved dematia bending effect as shown in Table XV (1) versus improved rubber pair as shown in Table XV (2) versus non-pitch properties including the control formulation. 1 shows a coal tar pitch-containing composition having rubber adhesion and improved thermal properties.

Intermediate Phase Pitch Furthermore, another preferred embodiment of the present invention contemplates a wide range of distillates used to generate the intermediate phase pitch.

  While preparing a high softening point (SP) pitch (140-240 ° C. SP), a distillate (top) is also produced. The top of the column contains less than 0.1% by weight of quinoline insolubles (QI) and less than 1% by weight of toluene insolubles (TI). The material mainly contains aromatic hydrocarbons with boiling points above 250 ° C. (highest boiling point above 380 ° C.). Due to its aromatic character and solids deficiency (QI), the top can be converted to an intermediate phase under suitable processing conditions. The mesophase is usually defined as the optically anisotropic liquid crystalline carbonaceous phase or the pitch formed from the top under appropriate conditions. The mesophase pitch can be used for special applications such as carbon / carbon composites, lithium batteries, heat treatment equipment, foams and mesocarbon beads (mesocarbon granules).

  By various heat treatment methods, the intermediate phase can be produced to a concentration ranging from less than 1% by volume to more than 80% by volume.

Example 10
About 500 grams of the top was heat treated to 400 ° C. in a 500 ml glass reactor under a nitrogen atmosphere sweep at 750 cc / min. After 40 hours, the mesophase content was 0.9% by volume but increased to 46.0% by weight after 68 hours.

Example 11
In the same apparatus as used in Example 1, the top was heat treated at 440 ° C. After 35 hours, the mesophase content was 80.2% by volume.

Example 12
The top product was initially distilled to 107 ° C. SP pitch by vacuum distillation by heat treatment during distillation. The resulting pitch (1.1 vol% intermediate phase) was heat treated in a 20 ml crucible with a lid at 450 ° C. for 2 hours. The intermediate phase content was 76.6% by volume. The pitch was heat treated at 430 ° C. for 3 hours in a crucible to produce an intermediate phase content of 15.8% by volume. The test was performed in a furnace without nitrogen purification.

Example 13
The top was heat treated in a 100 ml glass reactor at 430 ° C. for 15, 17 and 19 hours. The mesophase contents were 6.9, 35.3 and 81.8% by volume, respectively. Nitrogen was swept through the heat treated material at a rate of 450 cc / min.

Example 14
The tower top not heat-treated was distilled under reduced pressure to a soft pitch (54.0 ° C SP). Thereafter, along with nitrogen purification, the soft pitch was heat-treated in a 100 ml glass reactor. After 39 hours at 400 ° C., the mesophase was 3.9% by volume. Moreover, as a result of heat-treating the soft pitch for 31 hours in a temperature range of 430 ° C. to 455 ° C. for a total of 31 hours, the intermediate phase content was 82.4% by volume.

Example 15
5% oxygen was added to the purification gas and the top was heat treated at 440 ° C. in a 100 ml glass reactor. After 8 hours, the mesophase content was 19.8% by volume. The properties of the mesophase changed with the presence of oxygen. The coalescence of mesophase globules into macrospheres or mosaic structuring was prevented. Individuality of 10 μm spheres was maintained.

Example 16
Along with nitrogen purification, a large amount (about 2 kg) of mesophase material was prepared in a 4 liter glass reactor. The tower top was heat-treated at a temperature range of 410 ° C. to 440 ° C. for 36 hours. The intermediate phase content of the product was 28.8% by volume.

Carbonized preform
Example 17
The procedure for forming the short carbon fiber carbonized preform 10 is as follows (FIGS. 1 to 4).

  1. Create mold platen 12 (machined to finished dimensions) to match the internal and external dimensions required for the final preform. The height of the mold platen 12 should be larger than the finished dimensions of the press plate 14 (FIG. 1b).

  2. Create removable inner sleeve 16 and outer sleeve 18 to be several times the height of the preform mold. An inner sleeve 16 and an outer sleeve 18 are disposed on the mold 12 (FIG. 1b).

  3. Short carbon fibers 20 are blended at a specific depth in the stamping die 12 and the inner sleeve 16 and outer sleeve 18 to reach the required final carbon fiber volume after the consolidation step (FIG. 1b).

  4. The perforated press plate 14 is disposed on the short carbon fiber 20, and the short carbon fiber 20 is press-molded to a predetermined height (FIGS. 2a and 2b).

  5. The perforated press plate 14 is locked in place (FIG. 2a) by means of a locking device 22, such as a steel pin.

  6. Remove inner sleeve 16 and outer sleeves 1 and 8 (Figure 3).

  7. A vacuum / pressurization chamber 24 is arranged on the molding die 12 and the vacuum / pressurization chamber 24 is sealed to the molding die 12 (FIG. 4).

  8. Depressurize the vacuum / pressurization chamber 24 and the mold platen 12 (FIG. 4).

  9. Liquid coal tar pitch 26 having a softening point of 140 ° C. or higher is introduced into mold platen 12, and the interior of short carbon fiber is filled with liquid coal tar pitch 26.

10. 2.09kg / cm ² (30psi) or more nitrogen pressure vacuum / pressure chamber 26 and the mold plate 12 and the pressurizing, the short carbon fibers is fully saturated.

  11. Release pressure and remove vacuum / pressurization chamber 24.

  12. Cooling the mold platen 12 to carbonize the preform 10 in the mold platen 12.

  13. Remove perforated press plate 14 and carbonized preform 10.

Example 18
Using the following steps, disperse the short carbon fibers uniformly in the preform mold and bond (appropriately fix) the fibers without using a phenolic resin (FIGS. 1-3, 5 and 6). To form a short carbon fiber preform using a coal tar pitch binder having a high softening point.

Step 1. Create mold platen 12 with internal and external dimensions of required final preform size (can be machined to final dimensions). The height of the mold platen 12 should be greater than the final dimension so that the press plate 14 can be placed (FIG. 1b).

  2. Create an inner sleeve 16 and an outer sleeve 18 that are detachable several times the height of the preform mold. An inner sleeve 16 and an outer sleeve 18 are disposed on the mold 12 (FIG. 1b).

  3. Mix a large amount of short carbon fibers, pulverized (powdered) high softening point coal tar pitch having a softening point of 140 ° C. or higher, and other friction additives such as graphite and / or coke. .

  4. Disperse the mixture of 3. above uniformly in the mold platen 12, the inner sleeve 16 and the outer sleeve 18 (FIG. 1b).

  5. A perforated press plate 14 is placed over the mixture and the mixture is pressed to a predetermined preform height (FIG. 2a).

  6. Fix the perforated press plate 14 in the optimum position of the locking device 22 (FIG. 2a).

  7. Remove inner sleeve 16 and outer sleeve 18 (FIG. 3).

  8. The perforated press plate 14 and the mold 12 are fired at 800 ° C., and the high softening point pitch is melted and carbonized in the mold 12.

  9. Cool and remove the perforated press plate 14 and the carbonized preform. When it is difficult to take out the preform, the preform may be drawn out using the preform take-out jig 28 shown in FIGS. The preform take-out jig 28 is a steel plate 30 having a central sleeve 32. The preform take-out jig 28 may be pulled out using an attachment device 34 disposed on the central sleeve 32. Further, when the preform is pulled out, a lip 36 (preferably 1.27 cm (1/2 inch)) to be fixed below may be provided on the preform.

  In the above steps, steps can be added or deleted as long as the obtained product is not substantially affected.

  In this specification, unless expressly indicated to the contrary, similar components and / or methods disclosed elsewhere herein and all of the above components and / or steps are interchanged where appropriate. Can be considered as possible.

  The entire contents of any and all patents, patent publications, papers and other publications discussed or specified in this specification are intended to be described herein, unless otherwise stated in the specification. , Incorporated herein by reference.

  Although the present invention has been described in detail with reference to the drawings and preferred embodiments that are presently considered to be the most practical and preferred embodiments, the above detailed description is merely for the purpose of explanation and the present invention. It will be understood that the invention is not limited to the disclosed embodiments, but on the contrary is intended to encompass modifications and equivalents within the spirit and scope of the claims.

Plan view of preform molding die 1 is a cross-sectional view taken along the line AA in FIG. 1, showing a preform molding machine in which an inner sleeve and an outer sleeve are detachably inserted. Cross-sectional view of preform mold platen with perforated press plate Plan view of perforated press plate Cross-sectional view of preform molding platen with removable inner sleeve and outer sleeve removed Cross-sectional view of preform mold platen with vacuum / pressurization chamber Sectional view of a preform molding die according to another embodiment Plan view of preform removal jig

Explanation of symbols

  (10) ・ ・ Carbonized preform, (12) ・ ・ Molding die, (14) ・ ・ Press plate, (16) ・ ・ Inner sleeve, (18) ・ ・ Outer sleeve, (20) ・ ・ Short carbon fiber , (24) ・ ・ Vacuum / pressurization chamber, (26) ・ Liquid coal tar pitch, (28) ・ Preform removal jig,

Claims (5)

Placing the removable inner sleeve and the removable outer sleeve on the mold platen;
Blending short carbon fibers in the mold platen, inner sleeve and outer sleeve;
Pressing the short carbon fiber with a press plate;
Removing the inner sleeve and the outer sleeve;
Sealing the vacuum / pressure chamber in the mold platen and applying vacuum pressure to the vacuum / pressure chamber;
Introducing a liquid coal tar pitch into the mold platen;
Pressurizing the vacuum / pressurization chamber with nitrogen;
Releasing the pressure and removing the vacuum / pressure chamber;
Cooling the mold platen;
A method for producing a carbonized preform comprising a step of taking out a press plate and a carbonized preform.   A carbonized preform formed by the manufacturing method according to claim 1. Placing the removable inner sleeve and the removable outer sleeve on the mold platen;
Blending a powdered high softening point coal tar pitch and a short carbon fiber into a molding die, an inner sleeve and an outer sleeve;
Pressing the short carbon fiber with a press plate;
Removing the inner sleeve and the outer sleeve;
Baking the mixture in the mold platen;
Cooling the mold platen;
A method for producing a carbonized preform, comprising a step of removing a press plate and a carbonized preform from a molding die.   The manufacturing method of Claim 3 which further includes the process of taking out preform from a shaping | molding die board using a preform taking-out jig | tool.   A carbonized preform formed by the manufacturing method according to claim 3.

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