Abstract: This invention provides a commercially advantageous process for producing a foamed article of an aromatic polyester, especially a large-sized foamed article of aromatic polyester having a high expansion ratio. The process comprises mixing an aromatic polyester, a polyepoxy compound, a compound of a metal of Group Ia, IIa or IIIa of the periodic table and a blowing agent in a melt extrusion molding machine optionally with a fibrous filler while introducing the blowing agent thereinto under pressure, extruding the molten mixture from the molding machine, further expanding the foamed unsolidified extrudate in an atmosphere maintained at reduced pressure, and solidifying it by cooling in an atmosphere maintained at reduced pressure. The resulting aromatic polyester foamed article has numerous fine cells having uniform volumes, shapes and distribution.

Abstract: A glass fiber-reinforced thermoplastic polyester composition comprising(A) 100 parts by weight of polyethylene terephthalate having an intrinsic viscosity, measured at 35.degree. C. in ortho-chlorophenol, of from 0.4 to 0.9,(B) from 0.05 to 3 parts by weight of a salt of montan wax,(C) from 5 to 200 parts by weight of glass fibers having an average length of at least 0.2 mm, and(D) from 0 to 5 parts by weight of an epoxy compound having at least two epoxy groups in the molecule.