The invention provides a method for producing a foamed article comprising
the steps of: heating a mixture comprising (a) 100 parts by weight of
linear saturated polyester, (b) 0.1 to 10 parts by weight of a mixture as
a coupling agent of 0 to 100% by weight of a compound having two epoxy
groups in the molecule, and 100 to 0% by weight of a compound having two
or more epoxy groups, and (c) 0.01 to 5 parts by weight of a metal salt of
a carboxylic acid as a coupling reaction catalyst, at a temperature of a
melting point of the polyester or more to provide a melt flow rate of 50
g/10 minutes or less and swell of 10 to 200%, whereby a polyester resin is
formed; and heating and foaming the polyester resin using a foaming agent
. A foamed article useful as cushioning material, heat insulating
material, packaging material, food container, and dividers can be produced
by increasing the molecular weight, melt viscosity, and swell (degree of
swelling) of PET-based polyesters that have relatively low molecular
weight and are brittle, especially recovered polyester, that is used as a
prepolymer.
