because dioxin and furan of which the toxicity is high arise, when halide fire retardant burns. Therefore, the use of halogen-free system fire retardant such as phosphorus system fire retardant has increased year by year. However, the improvement of reliability of substrates using halogen-free system fire retarding material becomes an important problem, since there is fears that strength and heat-resistance are inferior to conventional substrates. . The safety assessment of halogen-free substrates is only to carry out simple evaluations by tensile test, etc. So the evaluation on fatigue reliability has not been almost carried out. Then, fatigue reliability of halogen free substrate was evaluated in this study. Especially, this study was demonstratively carried out by investigating the difference of fatigue fracture mechanism between conventional halogen substrate and halogen-free substrate from a viewpoint of mesoscopic fracture mechanism. EXPERIMENTAL METHOD Sample materials used in this investigation were halogen free-laminated material MCL-RO-67G made by Hitachi Chemical Co., Ltd. New aromatic system addition reaction type thermosetting resin (RO resin) of which fire resistance was high had mainly been used for this laminated material. Therefore, fire-retardant UL94V-0 has been achieved, even if this material does not use the halide fire retardant such as halogen compound, antimony and red phosphorus. Especially, it has high elastic modulus and heat-resistance under the high temperature environment, since it mainly has the aromatic skeleton in molecular structure, (Table 2). And, the general FR-4 laminated material was prepared in order to compare characteristics of a conventional halogen laminated material. The molecular structure of halogen resin is shown in Fig.2. In either sample, the glass cloth has been used as reinforcement. Test specimens were machined in dambell-type. Fatigue test with a minimum/maximum load ratio R of 0.1 were carried out under 10Hz-loading rate at sine wave in ordinary-temperature. And the fatigue test equipment was computer control servo fatigue testing machine made of Shimadzu Co.,Ltd.. Tabel 1 A series of research result on reliability assurance of recycling engineering plastic M atrix Reinforcem ent m aterial Tested Method Environment Recycling property PA66 Carbon fiber Fatigue test Above Tg/Below Tg △ Fatigue crack propagation test Above Tg/Below Tg △ Glass fiber Fatigue test Above Tg/Below Tg × Fatigue crack propagation test Above Tg/Below Tg × PA46 Carbon fiber Fatigue test Above Tg/Below Tg △ Fatigue crack propagation test Above Tg/Below Tg △ Glass fiber Fatigue test Above Tg/Below Tg × Fatigue crack propagation test Above Tg/Below Tg × Aramid fiber Fatigue crack propagation test Room △ PEEK Carbon fiber Fatigue test Above Tg/Below Tg ◎ Fatigue crack propagation test Above Tg/Below Tg ◎ Glass fiber Fatigue test Above Tg/Below Tg ○ Fatigue crack propagation test Above Tg/Below Tg ○ PPS Glass fiber Fatigue crack propagation test Room × C arbon fiber ＋ Fatigue crack propagation test Room △ Tetrapoded fiber PA･MXD6 Glass fiber Fatigue crack propagation test Room × Grass fiber Carbon fiber Tetorapoded - shaped whisker Aramid fiber Broken Bulge Recycling molding process ＰＰＳ, MXD6, PA46, PA66 Declining of the fiber length is big Grass fiber Carbon fiber Hard to break Recycling molding process Declining of the fiber length is small ＰEEK O Brm O O Brm Combustion Polybromodiphenyl - oxide Polybromodibenzo - dioxin Brm O Brm Combustion Polybromodiphenyl Polybromodibenzo - furan (m = 1～4, n = 1～4) Fig.1 Schematic of influence of recycling Fig.2 Formation of dioxin and furan molding process of FRTP on previous study
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