Did you know?

Jons Jacob Berzelius produces in 1847 first condensation polymer : polyester, derived from glycerin (propanetriol) and tartaric acid. Berzelius is also credited coining the chemical terms allotrope, catalysis, isomer and polymer.

In 1865 Alexander Parkes was the first man made plastic by dissolving cellulose nitrate in alcohol and camphor containing ether. Resulting substance was transparent and easily molded when hot, but retained hardness while cold. He named this plastic compound called Parkesine.

Observing the first Injection machine :

Fig.1:John W. Hyatt 1837-1920

In 1868, John W. Hyatt (fig.1) patented a process that produced a product he called celluloid, which he used as a replacement for ivory in billiard balls. Just four years later, in 1872, he became the first to inject hot celluloid into a mold. He and his brother Isaiah patented an injection molding machine that used a plunger to inject plastic through a heated cylinder and into a mold. Some of the early products created using celluloid included collar stays, buttons and, as the hairstyles of the day grew longer, hair combs.

The initial molding machine was based on a fairly simple mechanism. The process was improved by German scientists who managed to create less flammable solutions by developing soluble forms of cellulose acetate.

Fig.2:Patent drawings for the Hendry injection moulding machine.

World War Two and the Brave New World

This demand following World War II was in part a result material shortages. For example, rubber production was disrupted by the war across Asia and attacks on shipping lanes. Tanks and other war applications created a huge demand for metal. Plastics stepped in to fill the gap, providing an affordable substitute. As plastics gradually popularized, so too did plastic injection molding. It’s effectiveness to this era was primarily attributed to efficient, affordable, large-scale manufacturing.

By 1946, American inventor James Watson Hendry built the world’s first extrusion screw injection machine(fig.2). Using a rotating screw, Hendry was able to better control the injection process itself. This dramatically increased the quality of the products produced. Hendry wasn’t done after creating the extrusion screw injection machine. Far from it.

Pit Stops:

  • 1955-65In the mid-1950s a number of highly useful new thermoplastics become available. High-density polyethylenes produced by the Phillips process and the Ziegler process are marketed and shortly followed by the discovery of polypropylene. Acetyl, ABS and polycarbonates are also developed.
  • 1956W. H. Willert reciprocating screw plasticator patent issued – the next development from the extrusion system. In reciprocating systems the screw moves backwards and forwards during the mould cycle. After mixing, the screw stops turning and the entire screw pushes forward, acting like a plunger for injecting material into a mold. During plastication, the screw moves backward against the hydraulic back pressure. (Fig.3)
Fig.3 Willert-Injection-Moulding-Machine
  • 1960s Polysulphones, the PPO-type materials, aromatic polyesters and polyamides introduced.
  • 1970s James Watson Hendry went on to develop the first gas-assisted injection molding process, which permitted the production of complex, hollow articles that cooled quickly. This greatly improved design flexibility as well as the strength and finish of manufactured parts while reducing production time, cost, weight and waste.
  • 1972 Parts removal robots used in injection moulding process.
  • 1973 OAPEC oil crisis. First real point of considering dependence on plastics on oil and other materials.
  • 1979Plastic production overtakes steel production.
  • 1985 All-electric molding machine produced by Japanese firm.
  • 1990Aluminum molds first used widely in injection molding.

As we can see today the world of plastic is in a huge progress, each day we have a new invention which make our life more easier. In Copar we always try our best to satisfy our customer and stay connected to the new innovations.

Resources: Wikibooks, Kaso, Nbplastics, Wundermold.