Injection molding arrangement with improved preform cooling.

摘要

An injection molding machine and method for injection molding preforms, in which the preforms are rapidly cooled by release into a cooling water bath (22) after injection molding thereof. The injection molding machine includes a stationary platen (12) supporting a plurality of exterior preform mold cavities (14) and a movable platen (16) supporting a plurality of interior preform core rods (18) and neck split ring molds (20). An interior preform core rod (18) and a neck split ring mold (20) are associated with and positioned adjacent to each of the plurality of exterior preform mold cavities (14) during molding of the preforms. A cooling water bath chamber (22) with an open top (24) is positioned below the movable platen (16). After the formation of the preforms to the point whereat the outer skins of the preforms are hardened and below the glass transition temperature, the movable platen (16) is displaced away from the stationary platen (12). The neck split ring molds (20) displace the preforms from the core rods (18), and then the neck split ring molds (20) are opened to release the preforms into the cooling water bath chamber (22). The preforms sink into the cooling water bath, and are cooled very rapidly by cooling water contacting all exterior and interior surfaces of the preforms. A lubricant additive such as an emulsion of oxidized polyethylene is preferably added to the cooling water to provide lubricant coatings for the preforms to prevent possible damage to preforms which contact each other in the cooling water bath or thereafter during handling. <IMAGE>