| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin-walled lightweight resin molded article excellent in strength and rigidity, having good appearance free from a sink, warpage and deformation and having a surface density of 0.2 g/cm2 or less. SOLUTION: Fiber reinforced thermoplastic resin pellets having a total length of 3-100 mm and containing 15-90 wt.% of fibers having length equal to the total length and arranged in parallel to each other are melted and kneaded to be injected (compressed) and charged in a mold cavity and the vol. of the mold cavity is expanded to produce an expanded molded article. In this method, (1) the cavity interval of the principal part of a mold at the time of the filling of a resin is set to 0.1-1.5 mm, (2) the temp. of the mold is set to (Tc-50 deg.C)-(Tc) on the basis of crystallizing temp. (Tc) in the case of a crystalline resin and set to (Tg-50 deg.C)-(Tg) on the basis of glass transition temp. (Tg) in the case of an amorphous resin and (3) an injection filling time is set to 4 sea or less.
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