Abstract: Single or multiple colorants are infused into a thermoplastic material during melt processing to form preforms and plastic containers exhibiting a marbleized or swirl-type pattern. A base resin and colorant may be fed into an extruder having an extrusion screw and/or barrel modified in a manner to cause incomplete and non-uniform mixing. The modifications may include notches in some of the flights along the extrusion screw, a reduction in the depth or omission of some of the flights, a reduction in diameter of the extrusion screw, or the provision of a marbleizing torpedo near the discharge nozzle. Other techniques include introducing the colorant into vents present along the barrel, using a barrier screw to keep the components separate along the length of the barrel, using a high pressure pump for introducing the colorant near the discharge nozzle, or using multi-material co-injection techniques for co-injecting the base resin and colorant.

Abstract: The present invention relates to an apparatus and process for injection molding polymer articles that reduces deposition of additives on the apparatus. Specifically, pressurizing of the mold cavity with a pressurized gas reduces the deposition of low molecular weight additives on the apparatus. Embodiments of the invention also include an apparatus for injection molding polymer articles comprising at least one pressurized gas inlet for introducing a pressurized gas into the mold cavity.

Abstract: The present invention relates to an apparatus and process for injection molding polymer articles that reduces deposition of additives on the apparatus. Specifically, pressurizing of the mold cavity with a pressurized gas reduces the deposition of low molecular weight additives on the apparatus. Embodiments of the invention also include an apparatus for injection molding polymer articles comprising at least one pressurized gas inlet for introducing a pressurized gas into the mold cavity.