The invention provides a blow molding and a method for producing it. The
blow molding is lightweight; its strength and rigidity per the unit weight
thereof are high; and its heat resistance, sound absorption, heat
insulation and sound insulation are all good. The blow molding is produced
inexpensively, and is useful for the parts of inlet systems for
internal-combustion engines, etc. The blow-molding method is for
fiber-containing thermoplastic resins, and comprises holding a parison
made of an inorganic fiber-containing, melt-expandable thermoplastic
resin, between a pair of facing splits of a mold, blowing the parison to
shape it, and thereafter optionally reducing the gaseous pressure inside
it to thereby expand the wall of the shaped article. The blow molding is
made of a thermoplastic resin, and it contains from 15 to 70% by weight of
inorganic fibers having a mean fiber length of from 1 to 20 mm, and has a
porosity of from 10 to 90%.
