Blow Molds

They are known by various names. Light-ups, Lawn Art, plastic kitsch, illuminated figures, or simply blow molds.

Blow molding is a plastic manufacturing process. In 1881, the first U.S. Patent was given to Celluloid Novelty Co. of New York for extruding a polymer (cellulose nitrate) into a parison. In a nutshell, a hollow tube, the parison, is filled with melted plastic, placed into a steel mold, inflated with air, forcing the plastic to the interior surface of a metal mold, the metal mold is opened when cooled, the item is removed and appropriately painted. Cellulose acetate was later used in the 1930’s, Low Density Polyethylene (LDP) came in the 1940s, causing the blow molding industry to explode when Monsanto started making plastic squeeze bottles.

Convention - Museum RoomThereafter, many other manufacturers started using the process to produce plastic containers in substitution for glass. In the 1950’s High Density Polyethylene (HDPE) and Polypropylene (PP) were used to produce containers for water, oil, and most importantly, the lowly milk jug. Early in the 1960s, enterprising manufacturers started producing blow molded Christmas decorations*. Bernard Edward Co., of Chicago, IL, later renamed Beco, Poloron Products of New Rochelle, NY, Union Products of Leominster, MA and NOMA/Tico were some of the first to produce blow molded Christmas decorations. They were later followed by Dapol, Lidco, Hamilton Skotch Corp., Sunhill, Bayshore, Bel-Air Plastics, Empire, General Foam and many others.

*Note: Blow molding is a distinct form of plastic molding as opposed to injection molding which is the older of the two processes; producing hard plastic, even walled pieces that are glued or bonded together.