Although Toray has done an excellent job in developing a tough epoxy resin system for carbon fiber, it was apparent that the matrix R&D focus in Japan is high- temperature resins. This was evident at all of the aerospace primes visited and at Mitsui Toatsu Chemical, Inc. This is to support Japan's ambitious space program mentioned earlier.

The focus on high-temperature resins was also obvious by the temperature and pressure capability of all the autoclaves that have been recently installed in Japan. While Mitsui Toatsu presented matrix research activities including glass fiber in polypropylene, their major effort was on a thermoplastic polyimide matrix for carbon fiber for PX/T800. Table 5.5 compares the properties of the PX/T800 composite with those of PEEK/AS4 and an epoxy with T300. These materials offer outstanding heat resistance, excellent toughness, and good processability.

Table 5.4
Mitsubishi Kasei Dialead
Coal Tar Pitch-Based Carbon Fiber

Table 5.5
PIX (Thermoplastic Polyimide) CF Prepreg

(Mitsui Toatsu Chemicals, Inc.)

Mitsui Toatsu has broad-based cooperation with companies and universities in Japan, Europe, and the U.S. It was very interesting that Mitsui Toatsu has annual sales of approximately $3.3 billion, spends $190 million on R&D (5.7% of sales), and has only 5,475 employees, 25% of whom are in R&D.

Published: April 1994; WTEC Hyper-Librarian