This invention relates to 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. Dual-ovenable trays and other types of food containers can be made utilizing the process of this invention. It is advantageous to utilize the process of this invention in making such articles because they are lightweight and can be made utilizing less polymeric materials.
本发明涉及一种制造轻质物品的工艺,该工艺包括(1)将热塑性
树脂组合物喂入挤出机,其中热塑性
树脂组合物由(a)约94-约99重量%的聚
对苯二甲酸乙二醇酯和(b)约1-约6重量%的至少一种聚烯烃组成;(2)当热塑性
树脂组合物处于熔融状态时,将惰性气体混入挤出机中的热塑性
树脂组合物;(3) 将含有惰性气体的热塑性
树脂组合物通过片材成型模头挤出,生产出基本无定形的蜂窝片材,该片材含有足够量的惰性气体单元,使蜂窝片材的密度在约 0.4 至约 1.25 的范围内;以及 (4) 在加热模具中对蜂窝板进行热成型,以生产轻质物品。利用本发明的工艺可以制造双孔托盘和其他类型的食品容器。利用本发明的工艺制作这些物品是有利的,因为它们重量轻,可以使用较少的聚合材料。