Method of cooling multilayer preforms
AssigneeContinental PET Technologies, Inc.
InventorsWayne N. Collette, Thomas E. Nahill, Suppayan M. Krishnakumar
Life of this patent
Estimating the term…
Abstract
Method of making multilayer preforms which resist delamination and in a reduced cycle time. A first array of preforms are molded onto a first array of cores in an associated array of mold cavities, the cores and preforms are removed from the mold cavities as soon as possible without significant physical preform deformation, and the preforms are then cooled on the cores while a second array of cores is positioned in the mold cavities. Cooling on the cores prevents delamination of the preform layers and reduces the in-mold cooling time. Providing multiple sets of cores on a rotating turret further reduces the cycle time compared to the prior art use of robotic cooling tubes.
Claims30
In a method of forming multilayer plastic preforms, wherein a first array of cores is positioned in an associated array of mold cavities, the mold cavities are filled to form a first plurality of multilayer preforms on the first array of cores, the first array of preforms are cooled in the mold by contact with the mold cavities and cores at a relatively high first rate of cooling, and the first array of preforms are then removed from the mold cavities for further cooling, the improvement comprising:
- reducing the cooling time in the mold by removing the first array of cores and preforms from the mold cavities as soon as the preforms are able to cool on the cores without significant physical deformation of the preforms;
- and
- cooling the multilayer preforms on the cores at a second cooling rate relatively lower than the first Cooling rate so as to maintain the preforms at a higher temperature for a longer time and enable an increase in molecular ordering, diffusion and/or bonding at the layer boundaries, thus yielding an improved delamination resistance.
Dependencies are inferred from the claim text.