Paneling – Distortion, side wall collapse of a container occurring during aging or storage. Paneling is caused by the development of a reduced pressure inside the bottle.
Parting Line – A mark on a molding or casting where the halves of mold meet in closing.
Permeability – (1) The passage or diffusion of a gas, vapor, liquid, or solid through a barrier without physically or chemically affecting it. (2) The rate of such passage.
PET (Polyethylene Terephthalate) – Known as thermoplastic polyester. PET has the unusual ability to exist in either an amorphous or highly crystalline state. The crystalline state is necessary for extruding the material. The amorphous state permits it to be oriented.
Plasticize – To soften a material and make it plastic or moldable by means of a plasticizer or the application of heat.
Polyethylene – A thermoplastic material composed of polymers of ethylene. It is normally a translucent, tough, waxy solid unaffected by water and a large range of chemicals.
Polypropylene – A tough, light-weight rigid plastic made by the polymerization of high-purity propylene gas in the presence of an organometallic catalyst at relatively low pressures and temperatures.
Polystyrene – A water-white thermoplastic produced by the polymerization of styrene (vinyl benzene).
Polyvinyl Chloride (PVC) – A thermoplstic material composed of polymers of vinyl chloride. PVC is a colorless solid with outstanding resistance to water, alcohols, and concentrated acids and alkalies
Pour-Out Finish – A container finish having uniform undercut lips as a sealing surface. The pour-out finish is designed to facilitate pouring without dripping.
Preform – Used in the blow molding processes. A heat-softened polymer is formed into a shape similar to a thick test tube with neck threads. This tube is subsequently inflated while inside a blow mold to create the shape of the desired article.
Programming – The extrusion of a parison which differs in thickness in the length direction in order to equalize wall thickness of the blown container. It can be done with a pneumatic or hydraulic device which activates the mandrel shaft and adjusts the mandrel position during parison extrusion (parison programmer, controller, or variator). It can also be done by varying extrusion speed on accumulator-type blow molding machines.
Push-Up – The recessed area on the bottom of a bottle designed to allow an even bearing surface on the outside edge to prevent the bottle from rocking. |