Abstract: A multi-cavity injection mold process, for simultaneously injection molding a plurality of multi-layer articles, having a single hot runner manifold system for the sequential supply of first and second molten molding materials to the cavities of the mold with each of the materials being supplied simultaneously to all cavities in equal quantities. The process also uses a core rod for each cavity in which a concavity is provided, adjacent the entry point of the materials into the cavity, to prevent the first injected material in an injection cycle from being washed from the end of the core rod by the second injected material, the use of a buffer of the first injected material in the neck region of the preform to compensate for variations in temperature of the cavities and material being distributed to different parts of the mold and the use of the first part of the metered quantity of the first to be injected material from the next injection cycle to seal the preform at the end of the injection cycle.

Abstract: An apparatus and associated method of separating mixed fragments of different plastic materials, in which the materials to be separated are capable of carrying electrostatic charges of opposite polarities. The mixed charged fragments are given an induced electrostatic charge and are then exposed to electrostatic field of opposite polarities where they are separated by being allowed to migrate toward their respectively oppositely charged fields. The separated material fragments are then collected.

Abstract: A multi-cavity injection mold, for simultaneously injection molding a plurality of multi-layer articles, having a single hot runner manifold system for the sequential supply of first and second molten molding materials to the cavities of the mold with each of the materials being supplied simultaneously to all cavities in equal quantities. The invention also provides a core rod for each cavity in which a concavity is provided, adjacent the entry point of the materials into the cavity, to prevent the first injected material in an injection cycle from being washed from the end of the core rod by the second injected material, a buffer of the first injected material in the neck region of the preform to compensate for variations in temperature of the cavities and material being distributed to different parts of the mold and the use of the first part of the metered quantity of the first to be injected material from the next injection cycle to seal the preform at the end of the injection cycle.

Abstract: The present invention relates to an apparatus and method and uses a thin, yet strong plastic film as the intermediate layer for the waterproofing material and the film has a plurality of perforations therein. The film is highly resistant to crack propagation, and acts as a barrier to crack propagation between adjacent asphalt layers, thus providing superior protection from the elements. The asphalt layers are interconnected with each other through the perforations in the polyester support layer. Because of the strength of the polyester film, only a very thin layer of polyester is necessary and this results in a substantial cost savings. As an alternative to coating, it is possible to extrude or laminate the asphalt onto the PET film. Also a layer of asphalt may be applied only to one side of said film and extruded through the perforations with heads on the columns so formed to attach the asphalt to the film.