Japan pitch-based carbon fiber

Producers of PAN-based carbon fiber include Toray, Toho Beslon, Mitsubishi Rayon, and Asahi Kasai Carbon in Japan Hercules, Amoco Performance Products, BASE Stmctural Materials, Eortafil (Akzo), and Mitsubishi Rayon in the United States and Akzo, Sigri, and Soficar in Europe. Primary suppHers of high performance pitch-based carbon fibers include Amoco Performance Products, Mitsubishi Kasai, and Tonen Corp. 

Otani, S. and Oya, A, Progress of pitch-based carbon fibers in Japan, ACS Symp Ser, 1986, 303(22) (Petroleum-Derived Carbons), 323 334. 

Progress of Pitch-Based Carbon Fiber in Japan... 

Similarly, PZ pitch as precursor for HPCF was replaced by other mesophase pitches (12). At this point in time, as is well-known, Singer (13) and Lewis (14) of the Union Carbide Corporation developed similar methods. Mesophase carbon fiber progressed more rapidly in the USA than in Japan because Japanese defense and aerospace needs were less demanding. Recently, however, the drive toward higher-added-value products from the heavy fractions of coal and petroleum has intensified, and pitch-based carbon fibers, including HPCF, are now the subjects of extensive investigation in many Japanese laboratories. 

The principal problem in pitch-based carbon fiber is the control of the properties of the precursor pitch. Studies of pitch chemistry have contributed significantly to the development of pitch-based carbon fiber, including some investigations whose practical purpose was unrelated to carbon fiber. Since about 1969, a basic understanding of pitch chemistry has been pursued aggressively in Japan, and three studies of particular significance to carbon fiber are summarized here. 

A number of investigations of the preparation of pitch-based carbon fiber are in progress in industrial laboratories in Japan. However, aside from patents, only the developments by Honda and Yamada s group at the Kyushu Industrial Research Institute and by the present authors at Gunma University have been published. 

Source Reprinted with permission from Otani S, Oya A, Progress of pitch based carbon fiber in Japan. Bacha JD, Newman JW, White JL, eds., ACS Symp Ser No. 303, American Chemicai Society, Washington, DC, 322, 1986. Copyright 1986, American Chemicai Society. 

CMT Developments Co., Japan—a joint venture company originally set up between Toray Industries Inc. and Mitsui Coke Co. for research and development to produce pitch based carbon fiber. Company was dissolved in the latter part of the 1980s. 

Indemitsu Kosan Co., Ltd., Tokyo, Japan— Japanese State oil company, operates a petroleum pitch based carbon fibers plant. 

Mitsubishi Chemical Corp., Tokyo, Japan— produce a range of Dialead coal tar pitch based carbon fibers, with increasing thermal conductivity as the modulus is increased. Possess substantial know-how for making carbon-carbon. Offer the Replark line for retrofit of concrete structures. 

Nippon Graphite Fiber Corporation, Tokyo, Japan the carbon fiber business of Nippon Petrochemicals was forwarded to Nippon OU Co. in 1993 and in 1995, Nippon OU and Nippon Steel formed a joint company, Nippon Graphite Fiber Corporation, a pitch based carbon fiber business. This company make the world s smallest diameter (6 pm) pitch based carbon fiber. Produce Granoc yam the XN grades are based on petroleum pitch and YS grades are based on coal tar pitch. Produce woven fabric and supposedly have the lightest carbon fiber fabric at 60 gsm made from k pitch fiber (YT50 yarn). 

Toa Nenryo Kogyo KK, Kowasaki, Japan— produce a pitch based carbon fiber from Tonen s fluid catalytic cracking operations at Kawasaki. 

Tonen Corp., Tokyo, Japan—produce a range of Forca pitch based carbon fibers. 

The existence of carbon liber (CFs) came into being in 1879 when Thomas Edison recorded the use of carbon fiber as a filament element in electric lamp. Fibers were first prepared from rayon fibers by the US Union Carbide Corporation and the US Air Force Materials Laboratory in 1959 [41 ]. In 1960, it was realized that carbon fiber is very usefirl as reinforcement material in many applications. Since then a great deal of improvement has been made in the process and product through research work carried out in USA, Japan and UK. In 1960s, High strength Polyacrylonitrile (PAN) based carbon fiber was first produced in Japan and UK and pitch based carbon fiber in Japan and USA. 

Pitch-Based General Performance Carbon Fiber (GPCF). As described in the introduction, continuous-strand GPCF has been produced commercially only by the Kureha Chemical Industries Company. Public attention has recently been attracted to this type of carbon fiber by the success in using carbon-fiber-reinforced concrete in the construction of the Arsasheed Monument in Iraq (24) by the Kashima Construction (Kashima Kensetsu) Co. Future construction projects in Japan plan to utilize further this type of fiber-reinforced concrete. Such applications may lead to mass consumption of fiber if its price can be brought below 9/kg ( 4/lb). The authors believe that some substantial reductions in the price of the general-performance fiber, perhaps to 6.5/kg ( 3/lb), may occur in the near future. 

In comparison with the USA, the aerospace and defense industries of Japan are quite small. This is the principal reason for the relatively slow commercialization of pitch-based high-performance carbon fiber (HPCF) in Japan. As incentive for the HPCF industry, other fields of applications must be sought. In general, the... 

The introduction of HPCF by Union Carbide in the USA initiated intensive research and development to improve the processability of mesophase pitch (MP). Riggs and Diefendorf in the US worked on a neo-mesophase pitch based on a solvent extraction technique. Yamada and co-workers discovered the pre-mesophase pitch [41,42] using hydrogenation followed by a rapid heat treatment, while workers at the Kyushu Industrial Research Institute in Japan hydrogenated an anisotropic pitch (preferably a coal tar pitch), which after heat treatment produced a dormant mesophase pitch [43,44], a process known as the Kyukoshi method and able to produce a type of carbon fiber intermediate between a GP and HP fiber. Mochida and co-workers used a Lewis acid, such as AICI3, for the catalytic polymerization of an isotropic pitch, but found that an excessive amount of catalyst was required to achieve mesophase formation. 

Coal-derived pitch, prepared by a solvent-refining process, was used as a carbon fiber precusor for a short time by Britain s National Coal Board [27]. The process depended upon extensive filtration to remove mineral matter which would otherwise harm the carbon fiber s tensile strength this fact may explain why the process never reached commercialization. Other coal-based processes have been recently reported in Japan, slated for commercialization in 1986 or 1987. 

Other companies which have developed carbon fibers from mesophase pitch include Exxon Enterprises (who sold their carbon fiber technology to DuPont) and many Japanese companies. The Exxon work was based on extensive research at Rennselaer Polytechnic institute by Riggs and Diefendorf [32]. No commercial product, other than Union Carbide s, has appeared on the market except in sample quantities. However, based on technology developed by the Government industrial Research Institute, Kyushu, Japan, fourteen Japanese companies are trying to develop products of similar nature [331. 

Carbon fibers based on isotropic pitch have low strength and modulus with tensile strength averaging 870 - 970 MPa and modulus of 40 - 55 GPa (Datafrom Carboflex, Ashland Oil Co., Ashland, KY, and Kureha Chemicals, Japan). 

In Japan, the studies were facilitated by the access to the fusion (JT-60) and fission neutron reactor (JMTR, HTTR), for quite large samples, and by the know-how of Japanese industry in the field of carbon fibers and composites. PAN-based C fibers, instead of pitch-based ones (for 2D composites, with an ex-pitch C matrix), were chosen for irradiation tests (for fission application), since a larger fracture load and deformation could be obtained [34]. By the end of the 1990s, the main material studied in Japan was a 2D PAN-based C fiber/mix (ex-phenolic - - ex-pitch) C matrix material... 

---