Process for making lightweight polyester articles

A process for making an amorphous cellular sheet which can be thermoformed into lightweight thin walled articles which comprises:

• (1) feeding a thermoplastic resin composition into an extruder;
• wherein the thermoplastic resin composition is comprised of (a) from about 94 to about 99 weight percent polyethylene terephthalate, and (b) from about 1 to about 6 weight percent of at least one polyolefin:
• (2) mixing an inert gas into the thermoplastic resin composition while the thermoplastic resin composition is in the molten state:
• and (3) extruding the thermoplastic resin composition containing the inert gas through a sheet forming die to produce a substantially amorphous cellular sheet which contains a sufficient amount of inert gas cells to provide the cellular sheet with a density which is within the range of about 0.4 to about 1.25.

A process for making a lightweight article which comprises:

• (1) feeding a thermoplastic resin composition into an extruder, wherein the thermoplastic resin composition is comprised of (a) from about 94 to about 99 weight percent polyethylene terephthalate, and (b) from about 1 to about 6 weight percent of at least one polyolefin;
• (2) mixing an inert gas into the thermoplastic resin composition in the extruder while the thermoplastic resin composition is in the molten state:
• (3) extruding the thermoplastic resin composition containing the inert gas through a sheet forming die to produce a substantially amorphous cellular sheet which contains a sufficient amount of inert gas cells to provide the cellular sheet with a density which is within the range of about 0.4 to about 1.25:
• and (4) thermoforming the cellular sheet in a heated mold to produce the lightweight article.