Blow Molding: A Short History

Although plastics materials have been known since 1862, blow molding is not a new process. Many examples of glass blow-molded bottles and artifacts dating as far back as pre-biblical times have been discovered.

In the 1930s, plastics was blow molded for the very first time and was used for the production of hollow Christmas tree ornaments. Prior to that time, it was necessary to injection mold any hollow items in two separate parts and then either clip or seal them together with heat or adhesives.

The invention of low density polyethylene a few years later helped give birth to the new blow molding and plastic bottle industry. Progress and development was restrained until 1945, as all supplies of polyethylene were reserved for essential military applications such as radar antennas and connectors.

The very first recorded commercial plastics squeeze bottle was the “Stopette Powder Puffer” marketed in the USA in the late 1940s. At about the same time, the first production of lightweight, unbreakable, blow-molded pharmaceutical bottles began in England.

It was quickly followed by numerous other packaging applications, including the well known “Plastics Lemon,” which became an instant hit and marked the first time that any food item had been sold in a plastics container.

In the 1950s, the advent of high density polyethylene (HDPE), which had vastly improved characteristics, gave rise to many new applications and a further impetus to the fast-growing blow molding industry.

The basic principle of the process consists of admitting compressed air into an orifice or neck of a closed ended hot plastic tube so causing the plastics material to expand and then conform to the shape of a surrounding mold, allowing it to cool and then ejecting it from the mold. Today's need for high-speed, low cost and high quality mass production mandates the use of highly sophisticated equipment and many different types of processing machines are available. The process is now widely used for bottles from as small as 1/2 oz. to drums up to 60 gallons capacity, tanks, industrial items and medical devices, etc.

Strong Plastics is well-versed not only in the history of blow molding but also in the real-world application of this effective, low-cost process. Contact us now to put our expertise to work for your company.