초록 ▼

A multilayer plastic container having enhanced strength for high temperature and pressure applications such as the pasteurization of carbonated juice drinks. The container is commercially cost-effective in comparison to prior art pasteurizable glass containers, and provides all of the advantages of

A multilayer plastic container having enhanced strength for high temperature and pressure applications such as the pasteurization of carbonated juice drinks. The container is commercially cost-effective in comparison to prior art pasteurizable glass containers, and provides all of the advantages of plastic over glass, i.e., lightweight, shatter-resistant, etc. In a particular embodiment, the multilayer container includes inner and outer layers of a relatively high IV virgin PET, e.g., 0.85-0.90 dl/g, and a core layer of post-consumer PET having a substantially lower IV. The container has a relatively tall and slender profile, with high orientation levels in the panel and shoulder, and an oriented thick-walled base with feet. The base preferably has a high profile and angled foot pads which are allowed to move outwardly under creep. According to a method of making a multilayer preform for such container, an enhanced injection rate and mold pressure are utilized to enhance interlayer bonding and prevent separation of the layers in spite of their substantial differences in IV.

대표청구항 ▼

[ We claim:] [1.] A method of making a multilayer container, the method comprising the steps of:injecting a first thermoplastic material having a first intrinsic viscosity (IV) into a preform mold cavity at a first injection rate to form a first layer of a preform;injecting a second thermoplastic ma

[ We claim:] [1.] A method of making a multilayer container, the method comprising the steps of:injecting a first thermoplastic material having a first intrinsic viscosity (IV) into a preform mold cavity at a first injection rate to form a first layer of a preform;injecting a second thermoplastic material having a second IV, which differs by at least about 0.10 dl/g from the first IV, into the mold cavity at a second injection rate to form a second layer of the preform adjacent the first layer;applying a pressure to the first and second layers in the mold cavity, the injection rates and the pressure being selected to promote layer adhesion between the first and second layers; andblow molding a container from the preform which can withstand a 1 meter drop onto a hard rigid surface without layer separation.