Abstract: A method for thermoforming a cellular thermoplastic resin comprises exposing a cellular thermoplastic resin to a controlled humidity environment to obtain a conditioned cellular thermoplastic resin, molding the conditioned cellular thermoplastic resin to form a desired shape, and heating the conditioned cellular thermoplastic resin to cause the crystalline content of the thermoplastic resin to be at least about 20-30 percent. A method for conditioning a cellular thermoplastic resin comprises exposing a cellular thermoplastic resin to a controlled humidity environment to obtain a conditioned cellular thermoplastic resin.

Abstract: This invention is a composition and a kit to prepare the composition and articles made from the composition, which composition comprises polyethylene terephthalate, a nucleating agent having a defined Nucleation Index and optionally a polyolefin and a heat stabilizer. A particularly effective nucleating agent is polytetrafluoroethylene.

Abstract: This invention relates to a thermoplastic resin composition which is particularly suitable for use in thermoforming thin walled articles. The thermoplastic resin compositions are comprised of (1) from about 94 to about 99 weight percent polyethylene naphthalate and (2) from about 1 to 6 weight percent of at least one polyester elastomer. The subject invention also deals with thermoforming such thermoplastic resin compositions into articles, such as food trays, having a crystallinity within the range of about 10% to about 40%.

Abstract: A method of vulcanizing a tubular article by extruding a sheath of unoriented polyethylene terephthalate about the article followed by quenching the sheath to an amorphous state. The sheathed article is then subjected to vulcanizing conditions in order to convert the sheath from the low density amorphous state to the higher density crystalline state, thus compressing the article to effect a smooth finish.

Abstract: A molded extensible-collapsible container having a series of flutes, in the generic sense, in its side to permit the container when subjected to an external force to move to a collapsed position or to the extended position when preferably the yield point of the plastic is no greater than about 5% and it has an ASTM modulus of elasticity greater than about (6.895.times.10.sup.8 pascals) and less than about (2.758.times.10.sup.9 pascals) and preferably about (1.034.times.10.sup.9 pascals to 2.069.times.10.sup.9 pascals). The plastic of the blow molded container can be a blow moldable polyester of less than 5% elongation at yield with polyethylene terephthalate being most preferred.